Adjust atomics.wait, atomics.notify semantics for when they are used
with non-shared Wasm memory to mirror the spec change introduced
in: https://github.com/WebAssembly/threads/pull/147. This does not
need to be gated by the flag here, as this will only decode if
the flag is enabled.

Bug: v8:9921
Change-Id: I7f2e018fed6bd131ad4c386def1e838626c28a4d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2256863Reviewed-by: Ben Smith <binji@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68468}