Running the libfuzzer fuzzers locally (with an experimental flag turned
on) found crashes, but did not produce crash files because we were
generating a software interrupt ("trap") instead of properly aborting.
Disabling the "hard-abort" feature fixes that.

This will hopefully not flush out previously missed crashes. If so,
please do manually bisect across this CL, instead of assigning to me :)

Drive-by: Move more initialization logic from {InitializeFuzzerSupport}
to the {FuzzerSupport} constructor, where other similar work is
performed.

R=thibaudm@chromium.org, saelo@chromium.org

Bug: v8:13283
Change-Id: Id8d4e92f5ab6bb27676adeae6b3b1eb042b8ba3e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3892061Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Samuel Groß <saelo@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83208}