This adds heuristics to perform young and full GCs on allocation
of external ArrayBuffer backing stores.

Young GCs are performed proactively based on the external backing
store bytes for the young generation. Full GCs are performed only
if the allocation fails. Subsequent CLs will add heuristics to
start incremental full GCs based on the external backing store bytes.

This will allow us to remove AdjustAmountOfExternalMemory for
ArrayBuffers.

Bug: v8:9701, chromium:1008938
Change-Id: I0e8688f582989518926c38260b5cf14e2ca93f84
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1803614
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65480}