This prepares the trap handler to support being used from simulators.
Modifications to the arm64 simulator will be done in a follow-up CL. For
now, the trap handler will be registered but not used in Wasm (we emit
explicit bounds checks instead, as before).

The implementation uses inline assembly, so it is only available on x64
POSIX systems for now. This is the main platform we use for testing and
for fuzzing, so it should give us the test coverage we need. If needed,
inline assembly for other platforms can be added later.
The new code will be executed by the existing arm64 simulator bots, e.g.
"V8 Linux - arm64 - sim".

R=ahaas@chromium.org, mseaborn@chromium.org

Bug: v8:11955
Change-Id: Idc50291c704d9dea902ae0098e5309f19055816c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3011160
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75780}