The current implementation of the default ArrayBufferAllocator for the
virtual memory cage is highly inefficient as it simply forwards all
requests to the cage's PageAllocator. With this CL, this allocator is
now only used when the heap sandbox is enabled, in which case
ArrayBuffer backing stores must be located inside the cage. In all other
cases, in particular when only the virtual memory cage is enabled, the
backing stores can be located outside the cage and so the malloc-based
ArrayBufferAllocator is used.

This change only affects configurations in which V8's default
ArrayBufferAllocator is used.

Bug: chromium:1218005
Change-Id: I39cb5de3034ccd4b6975dc5193d8c7309857433b
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3205018Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77276}