This patch allows the concurrent marker to process more objects before
checking for the interrupt request from the main thread.

Bug: chromium:694255
TBR: mlippautz@chromium.org
Change-Id: I876d3156ca9843196f2fdddbd8bd28d1a3f472b1
Reviewed-on: https://chromium-review.googlesource.com/602131Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47182}