This CL disables the fallback to the experimental breadth-first regexp
engine which was enabled in 1e1f9ffc.

Bug: chromium:1157044
Change-Id: I669b18eddc15ea49aa58192102e719ae7f0364fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593250Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72001}