For checks and assertions (mostly for debug code, like stack alignment
or zero extension), we had two modes: Emit a call to the {Abort}
runtime function (the default), and emit a debug break (used for
testing, enabled via --trap-on-abort).
In wasm, where we cannot just call a runtime function because code must
be isolate independent, we always used the trap-on-abort behaviour.
This causes problems for our fuzzers, which do not catch SIGTRAP, and
hence do not detect debug code failures.

This CL introduces a third mode ("hard abort"), which calls a C
function via {ExternalReference}. The C function still outputs the
abort reason, but does not print the stack trace. It then aborts via
"OS::Abort", just like the runtime function.
This will allow fuzzers to detect the crash and even find a nice error
message.

Even though this looks like a lot of code churn, it is actually not.
Most added lines are new tests, and other changes are minimal.

R=mstarzinger@chromium.org

Bug: chromium:863799
Change-Id: I77c58ff72db552d49014614436259ccfb49ba87b
Reviewed-on: https://chromium-review.googlesource.com/1142163
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54592}