In ImageMagick 7.0.8-50 Q16, ComplexImages in MagickCore/fourier.c has a heap-based buffer over-read because of incorrect calls to GetCacheViewVirtualPixels.
### Prerequisites

- [x] I have written a descriptive issue title
- [x] I have verified that I am using the latest version of ImageMagick
- [x] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There is a heap buffer overflow in MagickCore/fourier.c:314:19 in .omp_outlined._debug__  

Heap buffer overflow sometimes occur. To trigger this bug,  please run the command for several times. 

### Steps to Reproduce
<!-- List of steps, sample code, failing test or link to a project that reproduces the behavior.
     Make sure you place a stack trace inside a code (```) block to avoid linking unrelated issues -->
run cmd:
`magick "-seed" "0" "-black-point-compensation" "-fuzz" "238" "(" "magick:logo" "-normalize" "-cycle" "615"  ")" "(" "magick:rose" "-gaussian-blur" "4" ")" "(" "magick:granite" "-convolve" "207,117,126,202,52,59,196,21,46,216,32,49,172,14,116,115,203,20,219,21,194,58,155,117,148,208,229,218,151,151,171,239,212,207,77,212,81,32,23,137,63,164,67,85,47,13,85,96,85,86,244,168,218,41,98,108,208,221,77,5,45,117,102,5,89,150,47,36,214,0,20,255,14,83,77,191,109,40,32,245,112"  ")" "-strokewidth" "58" "-complex" "subtract" "-layers" "compare-overlay" ""
`

ASAN log about heap buffer over-flow.
```
==18953==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x619000020200 at pc 0x0000014f4b4e bp 0x7fa64464bc30 sp 0x7fa64464bc28
READ of size 4 at 0x619000020200 thread T2
    #0 0x14f4b4d in .omp_outlined._debug__ MagickCore/fourier.c:314:19
    #1 0x14f56cc in .omp_outlined. MagickCore/fourier.c:231:3
    #2 0x7fa64f983452 in __kmp_invoke_microtask (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x7c452)
    #3 0x7fa64f93d1b6  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x361b6)
    #4 0x7fa64f93bb20  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x34b20)
    #5 0x7fa64f97b417  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x74417)
    #6 0x7fa651fb76da in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da)
    #7 0x7fa64f41f88e in clone (/lib/x86_64-linux-gnu/libc.so.6+0x12188e)

0x619000020200 is located 0 bytes to the right of 896-byte region [0x61900001fe80,0x619000020200)
allocated by thread T2 here:
    #0 0x4f09b0 in __interceptor_posix_memalign (install/bin/magick+0x4f09b0)
    #1 0x5822fa in AcquireAlignedMemory MagickCore/memory.c:265:7
    #2 0xb24539 in AcquireCacheNexusPixels MagickCore/cache.c:4968:37
    #3 0xb0d587 in SetPixelCacheNexusPixels MagickCore/cache.c:5076:12
    #4 0xb04b7c in GetVirtualPixelCacheNexus MagickCore/cache.c:2751:10
    #5 0xb28621 in GetCacheViewVirtualPixels MagickCore/cache-view.c:664:10
    #6 0x14f2984 in .omp_outlined._debug__ MagickCore/fourier.c:249:8
    #7 0x14f56cc in .omp_outlined. MagickCore/fourier.c:231:3
    #8 0x7fa64f983452 in __kmp_invoke_microtask (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x7c452)
    #9 0x7fa64f93d1b6  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x361b6)

Thread T2 created by T0 here:
    #0 0x43fcd0 in pthread_create (install/bin/magick+0x43fcd0)
    #1 0x7fa64f979110  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x72110)

SUMMARY: AddressSanitizer: heap-buffer-overflow MagickCore/fourier.c:314:19 in .omp_outlined._debug__

```

### System Configuration
<!-- Tell us about the environment where you are experiencing the bug -->

- ImageMagick version:
Version: ImageMagick 7.0.8-50 Q16 x86_64 2019-06-10

- Environment (Operating system, version and so on):
Description:	Ubuntu 18.04.1 LTS
Release:	18.04
Codename: bionic

- Additional information: CC=clang-7 CXX=clang++-7

<!-- Thanks for reporting the issue to ImageMagick! -->

heap-buffer-overflow in MagickCore/fourier.c
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : heap-buffer-overflow in MagickCore/fourier.c
Issue date:

--- start body ---
### Prerequisites

- [x] I have written a descriptive issue title
- [x] I have verified that I am using the latest version of ImageMagick
- [x] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There is a heap buffer overflow in MagickCore/fourier.c:314:19 in .omp_outlined._debug__  

Heap buffer overflow sometimes occur. To trigger this bug,  please run the command for several times. 

### Steps to Reproduce
<!-- List of steps, sample code, failing test or link to a project that reproduces the behavior.
     Make sure you place a stack trace inside a code (```) block to avoid linking unrelated issues -->
run cmd:
`magick "-seed" "0" "-black-point-compensation" "-fuzz" "238" "(" "magick:logo" "-normalize" "-cycle" "615"  ")" "(" "magick:rose" "-gaussian-blur" "4" ")" "(" "magick:granite" "-convolve" "207,117,126,202,52,59,196,21,46,216,32,49,172,14,116,115,203,20,219,21,194,58,155,117,148,208,229,218,151,151,171,239,212,207,77,212,81,32,23,137,63,164,67,85,47,13,85,96,85,86,244,168,218,41,98,108,208,221,77,5,45,117,102,5,89,150,47,36,214,0,20,255,14,83,77,191,109,40,32,245,112"  ")" "-strokewidth" "58" "-complex" "subtract" "-layers" "compare-overlay" ""
`

ASAN log about heap buffer over-flow.
```
==18953==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x619000020200 at pc 0x0000014f4b4e bp 0x7fa64464bc30 sp 0x7fa64464bc28
READ of size 4 at 0x619000020200 thread T2
    #0 0x14f4b4d in .omp_outlined._debug__ MagickCore/fourier.c:314:19
    #1 0x14f56cc in .omp_outlined. MagickCore/fourier.c:231:3
    #2 0x7fa64f983452 in __kmp_invoke_microtask (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x7c452)
    #3 0x7fa64f93d1b6  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x361b6)
    #4 0x7fa64f93bb20  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x34b20)
    #5 0x7fa64f97b417  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x74417)
    #6 0x7fa651fb76da in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da)
    #7 0x7fa64f41f88e in clone (/lib/x86_64-linux-gnu/libc.so.6+0x12188e)

0x619000020200 is located 0 bytes to the right of 896-byte region [0x61900001fe80,0x619000020200)
allocated by thread T2 here:
    #0 0x4f09b0 in __interceptor_posix_memalign (install/bin/magick+0x4f09b0)
    #1 0x5822fa in AcquireAlignedMemory MagickCore/memory.c:265:7
    #2 0xb24539 in AcquireCacheNexusPixels MagickCore/cache.c:4968:37
    #3 0xb0d587 in SetPixelCacheNexusPixels MagickCore/cache.c:5076:12
    #4 0xb04b7c in GetVirtualPixelCacheNexus MagickCore/cache.c:2751:10
    #5 0xb28621 in GetCacheViewVirtualPixels MagickCore/cache-view.c:664:10
    #6 0x14f2984 in .omp_outlined._debug__ MagickCore/fourier.c:249:8
    #7 0x14f56cc in .omp_outlined. MagickCore/fourier.c:231:3
    #8 0x7fa64f983452 in __kmp_invoke_microtask (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x7c452)
    #9 0x7fa64f93d1b6  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x361b6)

Thread T2 created by T0 here:
    #0 0x43fcd0 in pthread_create (install/bin/magick+0x43fcd0)
    #1 0x7fa64f979110  (/usr/lib/x86_64-linux-gnu/libomp.so.5+0x72110)

SUMMARY: AddressSanitizer: heap-buffer-overflow MagickCore/fourier.c:314:19 in .omp_outlined._debug__

```

### System Configuration
<!-- Tell us about the environment where you are experiencing the bug -->

- ImageMagick version:
Version: ImageMagick 7.0.8-50 Q16 x86_64 2019-06-10

- Environment (Operating system, version and so on):
Description:	Ubuntu 18.04.1 LTS
Release:	18.04
Codename: bionic

- Additional information: CC=clang-7 CXX=clang++-7

<!-- Thanks for reporting the issue to ImageMagick! -->

--- end body ---
