TST: Check series names
Related to #9972. Made `assert_series_equal` to check name attribute.

lgtm. any things that we need to put to watch out for in the future? e.g. where you needed to do `check_names=False` but couldn't check the name?
 As far as I know:
- `eval` using `numexpr` (#10239)
- `value_counts` (#10150)

But we may find further when adding `name` attribute to all `Series` in test cases.
 @sinhrks but you are testing this no? (e.g. you added it and fixed what was necessary)
 Ah, I meant the `name` attributes of existing test cases are all tested. But I didn't change test cases which uses `Series(..., name=None)` yet, and adding explicit name may reveal further problem. 

I'll continue to work on `Index` and `Series` metadata issues, hopefully change all test cases to have explicit name assignment like below (intends to be a fix for #10150):
- https://github.com/pydata/pandas/compare/master...sinhrks:base_name_handling
 ahh, I see. cool. ok let's merge this. thanks!
