For asm.js functions, the script name is used as the `source_url` for
code logging. If the script name was undefined, as it can happen for
asm.js code that gets evaluated in an eval, then `nullptr` was used
as the `source_url`. The problem was, the logging code accessed
`source_url` unconditionally, which caused a segfault.
With this CL the empty string is used as `source_url` instead of
`nullptr`.
The test revealed another problem in the isolate mode: profiling has
to be stopped and the profiler disposed before the isolate dies.
R=clemensb@chromium.org
Bug: chromium:1395401
Change-Id: Ia9730bb033a22b799ea2b1903ea540db9f259513
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4079685
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84892}
