This fixes a bug in which CompileTopLevel has a pending exception
that is never taken care of. This CL adds a check for the output
of CompileTopLevel and clears the pending exceptions if existent.

Also-by: bmeurer@chromium.org
Bug: chromium:1190290
Change-Id: Ieba537d5af78fc35475f9547c240c70850bea608
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2773346
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73561}