Avoid going through Heap but rather call it directly on the allocator.

Bug: v8:12615
Change-Id: I395b96d08b685c63c4125245a76c3610acf1643b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3485677Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79260}