Add HeapObject overloads for MarkingBarrier, GenerationalBarrier and
WriteBarrierForCode, which the compiler automatically prefers if a
setter's type is a subclass of HeapObject. These overloads can skip
the IsHeapObject check, providing maybe a small performance boost and
I measure a ~4.5kB binary size reduction in libv8.so

Change-Id: Ia65ff8425ae4895da406587101c7813fe6bf5a2b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1958055
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65395}