TeamDebugger:
- When a job is aborted, instead of calling into the user interface directly
to reset the status message, post a message to do so. Also, only post the
message if we aren't already in a terminating state. Otherwise, if jobs
were still running while the team debugger is executing its destructor, it
would attempt to make calls to the already destroyed user interface. This
bug has likely been with us for quite some time, but was hidden by incorrect
ref counting in the past (see #12343).