fctidz saturates the output in case of overflow. This cl
makes the behaviour similar to s390 and sets the output to zero.

Change-Id: Ic043625c46147eb02a65dfdbbcd883a067ba6981
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2527783Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#71061}