TST: Check index names

[sinhrks]

Derived from #9862. Added check_names kw to followings testing functions:

• assert_index_equal (default=True).
• assert_series_equal (default=True). Maybe the same option can be used to check Series.name in the future, otherwise it may better to choose separate name such as check_index_name.
• assert_panelnd_equal (default=False). We have to check following ToDo to specify default=True.
• https://github.com/pydata/pandas/blob/master/pandas/util/testing.py#L771
• assert_frame_equal is untouched as it already has the kw. Not refactored the logic because it has a path which doesn't use assert_index_equal internally.

Looked through test cases which have to be check_names=False, and added name check tests.

[jreback]

@sinhrks thanks!