Now that the maximum string length varies between platforms, the
correctness fuzzer is unhappy. It will ignore crashes, so when we know
we have reached platform-dependant behavior just crash if
--abort_on_stack_overflow is enabled.

Also rename abort_on_stack_overflow to
abort_on_stack_or_string_length_overflow.

Bug: chromium:748137
Change-Id: Ie4e96709b90029b5ce3c8408064d928f841b3b9f
Reviewed-on: https://chromium-review.googlesource.com/589269
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47007}