The implementation on wasm-bigint has been done, as far as I can tell.
There are no spec tests yet, only an out-dated copy of the original
spec tests which don't pass anymore. Therefore I disabled all the tests
for now and created a tracking bug at https://crbug.com/v8/9673.

R=adamk@chromium.org

Bug: v8:7741, v8:9673
Change-Id: I015846cc6008ad266402b6835e634723a1a076da
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1781050
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63541}