These tests unnecessarily rely on the `//# sourceURL` annotation. This
is preparatory work to eventually move the treatment of `sourceURL` to
the DevTools front-end.

Bug: chromium:1183990
Change-Id: I934eb1580f503b7b9f8d97c250b7c798bc67e268
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2814568
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73878}