lsprof: remove __main__ functionality
I'm pretty sure nobody uses this. I noticed it because Python 3
linting is complaining about execfile.
Differential Revision: https://phab.mercurial-scm.org/D7017
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.