This fixes the registered {protected_load_pc} to (always) point to the
actual load instruction. If {dst != src} we would emit a register move
before the load, and the trap handler would then not recognize the PC
where the signal occurs, leading to a segfault.

R=thibaudm@chromium.org

Bug: chromium:1242300, v8:12018
Change-Id: I3ed2a8307e353fd85a7ddedf6ecb73e90a112d32
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3136454Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76642}