This CL introduces a compile flag v8_enable_inner_pointer_resolution_osb
behind which lies the experimental implementation of the object start
bitmap. It disassociates the object start bitmap from the compile flag
v8_enable_conservative_stack_scanning. At the moment the former flag is
a prerequisite for the latter, as conservative stack scanning requires
some mechanism for inner pointer resolution and the object start bitmap
provides one such mechanism.

Bug: v8:12851
Change-Id: I24c6b389453fbaefc79ae50c34c5ec7a1bf23347
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3717322Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Nikolaos Papaspyrou <nikolaos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81295}