This CL also deprecates V8::RegisterDefaultSignalHandler. Now instead of
using the old API, clients should call V8::EnableWebAssemblyTrapHandler.
Just setting the --wasm-trap-handler flag will no longer have any
effect.

Bug: v8:5277
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Idd862185af9abcd4a3c845c02f9e916e8b56f114
Reviewed-on: https://chromium-review.googlesource.com/965005Reviewed-by: Karl Schimpf <kschimpf@chromium.org>
Commit-Queue: Eric Holk <eholk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52126}