Currently there is nothing ensuring the internal VM state of shared
objects are in a coherent state and visible to other threads when the
shared object is published.

This CL adds a store-store memory barrier when returning from Factory methods that allocate shared JSObjects that are exposed to user JS code. For primitives, there is an additional store-store memory barrier in the shared value barrier.

Bug: v8:12547
Change-Id: I4833c7ebf02cc352da9b006d2732669d6d043172
Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_isolates_rel_ng,v8_linux64_tsan_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3819041
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82596}