TST: Make numpy_array test strict
- [x] tests added / passed
- [x] passes `git diff upstream/master | flake8 --diff`

2 changes to make tests more strict:
- `assert_numpy_array_equal` now checks input is `np.ndarray`
- `assert_almost_equal` now checks inputs are the same class.

## [Current coverage](https://codecov.io/gh/pydata/pandas/pull/13311?src=pr) is **84.22%**

> Merging [#13311](https://codecov.io/gh/pydata/pandas/pull/13311?src=pr) into [master](https://codecov.io/gh/pydata/pandas/branch/master?src=pr) will decrease coverage by **<.01%**

``` diff
@@             master     #13311   diff @@
==========================================
  Files           138        138          
  Lines         50666      50667     +1   
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits          42672      42672          
- Misses         7994       7995     +1   
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last updated by [ae2ca83...7ae4e93](https://codecov.io/gh/pydata/pandas/compare/ae2ca83d31ebc2f95bb4f71b504f454ec399ee41...7ae4e93f98a436473db50018822e43eaafe0b61c)
 thanks!
