Apply pylint to remaining scripts in hiddenapi

1. Run pyformat scripts/hiddenapi -s 4
--force_quote_type none -i to fix formatting.
2. rename restricted variable names (e.g. variable name "input" has been
changed to "csvfile")
3. use pylint: disable=<X> where fixes are not obvious

Test: m merge_csv signature_patterns signature_patterns_test
Test: pylint --rcfile tools/repohooks/tools/pylintrc <file1>
<file1_test>
Bug: 195738175

Change-Id: I800a208f9c0ee1d32e68e4b20fd5933b3ab92c0e