- Disable automatic module file extensions for the test
- Use uncommon name suffix to prevent accidental loading of an
  existing file

Change-Id: I26c1092a1e559cbbebce442a8d5ff3fb6dd5aa84
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3122145Reviewed-by: Patrick Thier <pthier@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76616}