When V8 throws an uncaught exception, we store a JSMessageObject
with a stack trace and source positions on the isolate itself.
The JSMessageObject can be retrieved by a TryCatch scope
and is used by the inspector to provide additional information to the DevTools
frontend (besides the exception).

Introducing top-level await for REPL mode causes all thrown exceptions
to be turned into a rejected promise. The implicit catch block that does this
conversion clears the JSMessageObject from the isolate as to not leak memory.

This CL preserves the JSMessageObject when the debugger is active and stores
the JSMessageObject on the rejected promise itself. The inspector is changed
to retrieve the JSMessageObject in the existing catch handler and pass the
information along to the frontend.

Drive-by: This CL removes a inspector test that made assumptions when a promise
is cleaned up by the GC. These assumptions no longer hold since we hold on to
the promise longer.

Bug: chromium:1021921
Change-Id: Id0380e2cf3bd79aca05191bc4f3c616f6ced8db7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1967375
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65497}