[test] Mark early RegExp errors as FAIL_PHASE_ONLY

This ensures V8 at least throws the correct exception for these
tests, even if it happens at the wrong phase (i.e. at runtime
instead of at parse time).

Bug: v8:8467
Change-Id: I101aa2c7e073a56163c29e96e6c47f6ff0a01e53
Reviewed-on: https://chromium-review.googlesource.com/c/1375909Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58226}