Rewrite dict literal for files in pandas/tests/frame

[Qbiwan]

• xref CLN: C408 Unnecessary dict call - rewrite as a literal #38138

• tests added / passed

• passes black pandas

• passes git diff upstream/master -u -- "*.py" | flake8 --diff

• whatsnew entry
  identify unnecessary dict call - rewrite as a literal
  Rewrites as dictionary literals for the following files:

  modified: pandas/tests/frame/indexing/test_indexing.py
  modified: pandas/tests/frame/indexing/test_where.py
  modified: pandas/tests/frame/methods/test_fillna.py
  modified: pandas/tests/frame/methods/test_sort_values.py
  modified: pandas/tests/frame/methods/test_to_csv.py
  modified: pandas/tests/frame/methods/test_to_records.py
  modified: pandas/tests/frame/test_arithmetic.py
  modified: pandas/tests/frame/test_reductions.py

However, I did not change it to literal in the following two places, as they seem like valid dict call:

1. pandas/tests/frame/indexing/test_indexing.py

lambda l: dict(zip(l, range(len(l)))),   # line 76
lambda l: dict(zip(l, range(len(l)))).keys(),  # line 77

2. pandas/tests/frame/indexing/test_where.py

return DataFrame(dict((c, s + 1) if is_ok(s) else (c, s) for c, s in df.items()))  # line 32

[jreback]

both of 1 and 2 can be dict-comprehensions. (can do separately).