This fixes ~15 debug/inspector tests that were failing when
v8_enable_lazy_source_positions = true.

Bug: v8:8510
Change-Id: Ica02aa2ea84549b5cddd82b5b98835829f7b0f1b
Reviewed-on: https://chromium-review.googlesource.com/c/1477280
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59695}