tests/run-tests: Disable thread/thread_lock4.py on Travis.

It has reliability issues that need to be worked out.

Author: dpgeorge

tests/run-tests

@@ -200,6 +200,7 @@ def run_tests(pyb, tests, args):
     # Some tests shouldn't be run under Travis CI
     if os.getenv('TRAVIS') == 'true':
         skip_tests.add('basics/memoryerror.py')
+        skip_tests.add('thread/thread_lock4.py') # has reliability issues
 
     if not has_complex:
         skip_tests.add('float/complex1.py')