Enable the use of Heap::AlignWithFiller off-thread by making the method
static.

Bug: chromium:1075999
Change-Id: I8071ae678f954dd4e960b2cd83f63dd22a948920
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2184230Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67602}