This prevents the branch table iterator's has_next() method to trigger a
DCHECK when the decoder fails before the end of table decoding.

R=clemensb@chromium.org

Change-Id: I2258886501b77cd4c8fe98bc8a4ed0b66fb23066
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1864931Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64312}