tc-testing: gitignore, ignore standard python artifacts

Ignore .pyc files, "python compiled" files, that get created
when a python script is run.  They should never be committed.
Signed-off-by: NBrenda J. Butler <bjb@mojatatu.com>
Acked-by: NLucas Bates <lucasb@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tools/testing/selftests/tc-testing/.gitignore

 __pycache__/
+*.pyc