This is not used anywhere yet, and will be later used to gate
instructions like FMA (which is prototyped).

Bug: v8:11583
Change-Id: I2eac60cde6998490fcf3aee11c618ab5478346ee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2770605Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73519}