Calling {V8::Dispose} resets flag values, but error simulation relies on
{FLAG_random_seed}. Thus simulate errors before disposing V8.

R=machenbach@chromium.org

Bug: chromium:1168290
Change-Id: Ie3bc921d6dd1dbaece68ef0b801d8b25ba97585f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3315441Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78252}