This cl also adds a separate test suite for BigInts

Bug: v8:9213
Change-Id: I57271eed0f9c33a543fe15550964d55e3df3e963
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1596728
Commit-Queue: Nico Hartmann <nicohartmann@google.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61282}