Fix run_all_fuzzers.py bug.

Fixing a small logic error.

Bug: 326493647
Change-Id: Id2acc80dbb47921bd1752927c31a10752e054d08
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5359193


Auto-Submit: Adrian Taylor <adetaylor@chromium.org>
Commit-Queue: Adrian Taylor <adetaylor@chromium.org>
Reviewed-by: Adam Langley <agl@chromium.org>
Commit-Queue: Adam Langley <agl@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1270608}