Issue #17357: Use more stern wording for
importlib.invalidate_caches().
Issue #17857: Prevent build failures with pre-3.5.0 versions of sqlite3,
such as was shipped with Centos 5 and Mac OS X 10.4.
Issue #17842. Added base64 module tests with bytearray arguments.
Original patch by Kushal Das.
Added base64 module tests for non-binary files.