CLN: Specialize assert_(np.array_equal(...))

Work on #6175. This is the third (and final) "half" of the work started in #6368.
BUG: Bug in DataFrame.dropna with duplicate indicies (GH6355)
Merge pull request #6388 from jreback/dups_dropna

BUG: Bug in DataFrame.dropna with duplicate indices (GH6355)
DOC: add cookbook example for reading in simple binary file formats
Merge pull request #6390 from cpcloud/cookbook-read-bin-6305

DOC: add cookbook example for reading in simple binary file formats
API/CLN: add in common operations to Series/Index, refactored as a OpsMixin
         (GH4551, GH4056, GH5519)
Merge pull request #6380 from jreback/common_ops

API/CLN: add in common operations to Series/Index, refactored as a OpsMixin
Merge pull request #6387 from bwignall/assert_6175_arrayequal_3

CLN: Specialize assert_(np.array_equal(...))