os.path.join completion speed test is sometimes slow, so give it a bit more of time

test/test_speed.py

@@ -30,7 +30,7 @@ def _check_speed(time_per_run, number=4, run_warm=True):
     return decorated
 
 
-@_check_speed(0.2)
+@_check_speed(0.3)
 def test_os_path_join(Script):
     s = "from posixpath import join; join('', '')."
     assert len(Script(s).completions()) > 10  # is a str completion