pyfrc_test: Disable test_practice (#182)

This takes 14s on my laptop.

In practice, our fuzz tests likely hit more code paths than this test
which simply has the robot sit in one spot.

tests/pyfrc_test.py

@@ -2,12 +2,10 @@
 from pyfrc.tests import (
     test_disabled,
     test_operator_control,
-    test_practice,
 )
 
 # Make pyflakes happy about our imports.
 __all__ = (
     "test_disabled",
     "test_operator_control",
-    "test_practice",
 )