Make main-thread handle allocation fail more gracefully when run on
background threads.

Bug: v8:10315
Change-Id: Iece9215aed21020b97fede40d78ea56b9baffac4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2689184
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72646}