adding 2 new default arguments when running make check-wpt so that it does not fail saying KeyError: 'debug_args' or KeyError: 'interactive'
Update run.py

None and False are better values here (thanks to @jgraham).
Merge pull request #2808 from schaars/make_check-wpt

adding 2 default arguments to src/test/wpt/run.py; r=jgraham,Ms2ger