TST: better testing for test_where (GH8997)
closes #8996 

FWIW, as I have mentioned, not sure how this was supposed to help and here it is (not on current master but on v0.15.1-176-g526f33c as before

```
(Pdb) tm.assert_numpy_array_equal(result, expected)
*** AssertionError: [(0L, 'a') (1L, 'b') (2L, 'c')] is not equal to [(0L, 'a') (1L, 'b') (2L, 'c')]
```
 Hello,

I can confirm this od Debian build.
I have used a patch from #8996 and I did get the same result as yarikoptic

<pre>
======================================================================
FAIL: test_to_records (pandas.tests.test_categorical.TestCategoricalAsBlock)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/build/pandas-HjPP3c/TESTIRAJ_PANDU/2/pandas-0.15.1+git125-ge463818/debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_categorical.py", line 2393, in test_to_records
    tm.assert_numpy_array_equal(result,expected)
  File "/build/pandas-HjPP3c/TESTIRAJ_PANDU/2/pandas-0.15.1+git125-ge463818/debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py", line 632, in assert_numpy_array_equal
    '{0} is not equal to {1}.'.format(np_array, assert_equal))
AssertionError: [(0L, 'a') (1L, 'b') (2L, 'c')] is not equal to [(0L, 'a') (1L, 'b') (2L, 'c')].
</pre>

Regards,
Jurica
