A follow-up to crrev.com/c/3240782.

Drive-by: extend JSRegExp printing.

Fixed: chromium:1263327
Bug: v8:11069
Change-Id: Iff64ded27ca93641f0f572df2ce0a9f846948f7f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3245110
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77536}