Enable --concurrent-allocation to see whether this flag causes any
regressions.

Bug: v8:10315
Change-Id: Iafe80c048ad7f04186207c8c570f7cf85397f02f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2413260Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69948}