GitLab

Moves the splitting of expectations based on staleness out of the
output code and uses it to automatically remove stale expectations from
the expectation file if specified by the user.

Bug: 998329
Change-Id: I317ded44447203b8fddc2c6277ed3f5f5b66a0f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2585846Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836358}