Fix tags in fle2 tests and improve tag parser

Two fle2 tags are missing commas in the tag list
jstests/fle2/convert_encrypted_to_capped.js
jstests/fle2/fle2_retryable_writes.js

At the same time, the tags parser (buildscripts/resmokelib/utils/jscomment.py) in should detect this and error in this case.