Explicitly check for JSFunction or JSBoundFunction and throw if any other
JS type is passed to d8.test.verifySourcePositions.

Bug: chromium:1195717
Change-Id: Id65875526d5d6b3f720850d41d0a8192ec407035
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2807607
Auto-Submit: Patrick Thier <pthier@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73811}