Combine author_tag and log_translation_hint regexes

author_tag_re and log_translation_hints were lists of regexes, where
each member was then separately matched against each input line.

This change combines each of these lists into an a|b regex and removes
the unnecessary loop.

Change-Id: I8db76862d3f7ef030e31e2e1e6f2fcd8dbd00888
Merge "Combine author_tag and log_translation_hint regexes"