This CL adds a new boolean flag on the Debugger.setScriptSource CDP
method that gets piped all the way through to the live-edit mechanism.
The new flag enables live-editing of the top-most function while
paused.

The CL adds a couple of tests that cover the new core use cases for
this flag.

R=jarin@chromium.org

Bug: chromium:1334484
Change-Id: I12fec591b2b6550d89748714620e629548e1b9c1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3695354Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81127}