Registration of trap handler data has to happen *before* updating the
jump table, otherwise other threads might start using the code right
away, and if they hit a memory OOB, they just segfault if the trap
handlers have not been registered yet.

R=ahaas@chromium.org

Bug: v8:9375, chromium:980843
Change-Id: Ifac5c0681ce133b7af730a87beaede9d3c223f50
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687414Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62535}