Add ruleset_converter test utils

This is a pre-req to a refactoring effort splitting off logic
from main.cc and adding new tests.

This CL also changes rule_stream_test.cc -> rule_stream_unittest.cc

Bug: 833419
Change-Id: I9c73a336c2bae2fdbdbe7db68346c8c9a64be325
Reviewed-on: https://chromium-review.googlesource.com/1040045
Commit-Queue: Charlie Harrison <[email protected]>
Reviewed-by: Josh Karlin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#555486}
5 files changed