While writing a new test I realized that the test did not fail if
running into a CHECK or UNREACHABLE *after* printing the last expected
line.
That is because both stderr and the exit status are ignored. This CL
fixes that.

This will uncover a lot of memory leaks, which I plan to address in
follow-up CLs.

R=machenbach@chromium.org
CC=​szuend@chromium.org

Bug: chromium:1142437, v8:11107
Cq-Include-Trybots: luci.v8.try:v8_linux64_asan_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_mac64_asan_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_win64_asan_rel_ng
Change-Id: I65f325abf102e063bb4f449353c47e94d84de652
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2519567Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71006}