Move this straggler to its use-site in regexp-compiler.cc.

Bug: v8:9359
Change-Id: Ia5393140de5a1c8d70ac410ef6239eabfec130b3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1662303
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62241}