Disable h2 server from running via run_blink_wptserve.py

The h2 server turns itself on by default in wptserve, but we don't
support it in blinkpy yet. To avoid quietly grabbing port 9000, pass
--no-h2 to wpt for now.

Bug: 1090491
Change-Id: Ie326b86dd1305d1173740c85afc8eecded17e277
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2229582
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774951}

third_party/blink/tools/blinkpy/web_tests/servers/wptserve.py

@@ -58,7 +58,8 @@ class WPTServe(server_base.ServerBase):
         wpt_script = fs.join(path_to_wpt_root, 'wpt')
         start_cmd = [
             self._port_obj.host.executable, '-u', wpt_script, 'serve',
-            '--config', self._config_file, '--doc_root', path_to_wpt_tests
+            '--config', self._config_file, '--doc_root', path_to_wpt_tests,
+            '--no-h2',
         ]
 
         # Some users (e.g. run_webdriver_tests.py) do not need WebSocket

third_party/blink/tools/blinkpy/web_tests/servers/wptserve_unittest.py

@@ -33,6 +33,7 @@ class TestWPTServe(LoggingTestCase):
             server._config_file,
             '--doc_root',
             '/test.checkout/wtests/external/wpt',
+            '--no-h2',
         ])
 
     def test_init_start_cmd_with_ws_handlers(self):
@@ -48,6 +49,7 @@ class TestWPTServe(LoggingTestCase):
             server._config_file,
             '--doc_root',
             '/test.checkout/wtests/external/wpt',
+            '--no-h2',
             '--ws_doc_root',
             '/test.checkout/wtests/external/wpt/websockets/handlers',
         ])