This adds a little {Simulator::ProbeMemory} method that is used from
several places in the arm64 simulator to test if a memory address can be
accessed, and trigger a signal from a specific location such that the
trap-handler can handle it. In case of a trap, the simulator is
redirected to the landing pad and stops executing the memory
instruction that triggered the trap.

Standard memory accesses and SIMD memory loads and stores are
instrumented to probe the memory. This passes all existing tests. In
case this CL misses certain spots, we can still add them later. This
will not be a security problem, since we do not use the simulator in
production.

R=ahaas@chromium.org
CC=mseaborn@chromium.org, v8-arm-ports@googlegroups.com

Bug: v8:11955
Change-Id: I52a81341e99fabc5fcf9e41ef4d8dd2226092803
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3015557
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75843}