Drop test_cmdline_args.py

Before a couple weeks ago didn't know Tor had these tests, interesting! Stem already has tests for spawning tor processes but lacked any with this targeted focus on its arguments.

I've added our own counterpart for these tests. Many are direct copies but there were others I improved a little...

https://trac.torproject.org/projects/tor/ticket/14109 https://gitweb.torproject.org/stem.git/commit/?id=137d193a026638f066e817e3396cebbbb6ace012

Now that Tor uses Stem to supplement its tests no reason for these to live separately. Tested by simply building tor and confirming test_cmdline_args.py is no longer in the generated Makefile.

Patch will be uploaded in a sec...