Fix returning from TryAllocateLinearlyAligned without updating the
allocation stats if a preceding filler was required. Also makes
AllocateRaw take an int instead of size_t in line with other Spaces.

Bug: v8:8875, chromium:1097389
Change-Id: If0932caa94dce1cd45b41f44fa225a2007772ea1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2264354
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68516}