This was an oversight in https://crrev.com/c/3557234, which led to a
really weird developer experience: once a `window.onerror` handler was
installed, typing into the Console or other side-effect free debug
evaluations triggered this handler.

Fixed: chromium:1328008
Bug: chromium:1295750
Change-Id: I4029ff19ceb7cfe0a8eb6afff19c3ef9a4a82e25
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3660253
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80696}