Port 4ca8b4dd

Original Commit Message:

    This adds decoding and compilation of the "atomic.fence" operator, which
    is intended to preserve the synchronization guarantees of higher-level
    languages.

    Unlike other atomic operators, it does not target a particular linear
    memory. It may occur in modules which declare no memory, or a non-shared
    memory, without causing a validation error.

    See proposal: https://github.com/WebAssembly/threads/pull/141
    See discussion: https://github.com/WebAssembly/threads/issues/140

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:9452
LOG=N

Change-Id: Ib8ad24e65154d7555a47e537f81110be47f4d4de
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1710620
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62850}