This is a reland of 3600aabf

Original change's description:
> ppc: [liftoff] implement AtomicExch and AtomicCmpExch
>
> Change-Id: Ida66b9c42cfb9bd5b59a83188a2dfa0d602d4036
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3192427
> Reviewed-by: Milad Fa <mfarazma@redhat.com>
> Commit-Queue: Junliang Yan <junyan@redhat.com>
> Cr-Commit-Position: refs/heads/main@{#77148}

Change-Id: I84dc2d2c429c1f1646d0b97036ad9baa96961e56
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3216042
Commit-Queue: Junliang Yan <junyan@redhat.com>
Reviewed-by: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#77381}