This patch removes tracking of
- V8.GCIdleTimeAllottedInMS
- V8.GCIdleTimeLimit.Overshot
- V8.GCIdleTimeLimit.Undershot

BUG=chromium:751045

Change-Id: Iccaa0fff609d3caa4cf38ebcc8aca7cdca33c442
Reviewed-on: https://chromium-review.googlesource.com/595588
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47144}