Trap handler registration happens under a spin lock, which causes lots
of wasted cycles. With 48 background compilation threads, half of the
wall-clock time is being spent on that spin lock.
Moving this registration inside {PublishCodeLocked} avoids any lock
contention (if a single module is being compiled), since we already
sequentialize code publication. This speeds up background compilation
for large numbers of background tasks, and has no measurable effect for
small numbers.

R=ahaas@chromium.org

Bug: v8:8916
Change-Id: I572b53b9b581e4d5f6e441f6685350017d08d0be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1634928Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61957}