When the stack is split in safe and unsafe parts, on-stack
TracedReferences are allocated on the unsafe stack. What currently
happens is that on GC we destroy all the on-stack references below the
current frame of the *safe* stack. If the safe stack is allocated above
the unsafe counterpart, then all the traced references will be
preliminary destructed on GC. This CL fixes it by using
__builtin___get_unsafe_stack_ptr() if -fsanitize=safe-stack is enabled.

In addition, deduplicate OnStackTracedNodeSpace::IsOnStack() and
Stack::IsOnStack() and move more logic into ::heap::base::Stack.

Bug: chromium:1278780
Change-Id: I9582bb1321958b7ec8ef2c0c46b9e42d51bb6f94
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3395033Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Auto-Submit: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78660}