We want to replace all uses of CallOnForegroundThread eventually by the
new TaskRunner API so that we can eventually deprecate the old API and
remove it.

R=ulan@chromium.org

Bug: v8:8238
Change-Id: I7e451eddf05f1f7f273c5cfd57d82737380f3f02
Reviewed-on: https://chromium-review.googlesource.com/c/1261145Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56378}