So far we reported the script ID, but DevTools ignores that and uses the
source url instead. That url was just set to "wasm ", which the frontend
couldn't make any sense of.
This CL fixes this by passing the source URL to the code create event,
and also setting the position of the code inside the script (i.e.
wasm module).

R=thibaudm@chromium.org, petermarshall@chromium.org

Bug: chromium:1125986
Change-Id: Ic41dcd2768c60fd6748468d3a89fc4ffccb35932
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2581543
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71695}