Message 392303 - Python tracker

I'm going to set the line number for executing the `__exit__()` function as that of the `with` keyword.

This should give a sensible traceback, and not break coverage, as the with statement is already executed.
It will impact traces and profiles, which is why the __exit__ call was not given a line number before.

Anthony, Ned,
please let me know if you disagree.