Bug 1477574 [wpt PR 12135] - Don’t reverse-forward port "None", a=testonly

Automatic update from web-platform-testsMerge pull request #12135 from web-platform-tests/sync_978b7cfd464383fda222d57a5140c661e81381e9

Merge pull request #12135 from sync_978b7cfd464383fda222d57a5140c661e81381e9
--

wpt-commits: eee34eb8c23ef3c8d3cd7ff8772fc766245a3aa5
wpt-pr: 12135

testing/web-platform/tests/tools/wptrunner/wptrunner/browsers/servodriver.py

@@ -99,6 +99,7 @@ class ServoWebDriverBrowser(Browser):
             str(port)
             for _protocol, ports in self.server_ports.items()
             for port in ports
+            if port
         )
 
         debug_args, command = browser_command(