Temporarily disable stress-bytecode-flush on
mjsunit/regress/regress-786784 while we investigate failures related
to bytecode flushing.

Bug: v8:10560
Change-Id: Ieb5cc7ba87da04133e98c6be25c9a499d79543e0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2218038Reviewed-by: Marja Hölttä <marja@chromium.org>
Auto-Submit: Mythri Alle <mythria@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68046}