Remove some stray calls to setup_parser.

One is in help.py which is completely unused, so now deleted.

The other was in the new help printer.

Testing Done:
Verified that --help works.

CI passed.

Reviewed at https://rbcommons.com/s/twitter/r/1300/
Sync of https://github.com/pantsbuild/pants/commit/d4af7426824e4a871e60b469536223a0e46426b7