Debugger uses DisableInlineAllocation, this races with concurrent
allocation. Lock PagedSpace mutex for freeing the linear allocation
area.

Bug: v8:10315
Change-Id: If3b0c786943f99f7e9c7cefac9436e93b352e334
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2354811Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69394}