[wptrunner] Run wptrunner MVP tryjobs on WPT imports

To avoid unexpected breakages of the wptrunner MVP, we want to smoketest
it on the WPT importer. This will hopefully catch both upstream test
changes as well as infra changes that would break the MVP.

There is some risk that the bots might be unstable and unnecessarily
block imports. If this starts to happen, this commit should be reverted.

Cq-Include-Trybots: luci.chromium.try:linux-wpt-identity-fyi-rel,linux-wpt-payments-fyi-rel
Bug: None
Change-Id: Ie0dfde425bbdf4d21b2bee2f818697c29b1aa03a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2451504
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Reviewed-by: Luke Z <lpz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814213}

third_party/blink/tools/blinkpy/w3c/test_importer.py

@@ -553,7 +553,17 @@ class TestImporter(object):
         # Move any No-Export tag to the end of the description.
         description = description.replace('No-Export: true', '')
         description = description.replace('\n\n\n\n', '\n\n')
-        description += 'No-Export: true'
+        description += 'No-Export: true\n'
+
+        # Add the wptrunner MVP tryjobs as blocking trybots, to catch any test
+        # changes or infrastructure changes from upstream.
+        #
+        # If this starts blocking the importer unnecessarily, revert
+        # https://chromium-review.googlesource.com/c/chromium/src/+/2451504
+        description += (
+            'Cq-Include-Trybots: luci.chromium.try:linux-wpt-identity-fyi-rel,'
+            'linux-wpt-payments-fyi-rel')
+
         return description
 
     @staticmethod

third_party/blink/tools/blinkpy/w3c/test_importer_unittest.py

@@ -382,7 +382,9 @@ class TestImporterTest(LoggingTestCase):
             'https://chromium.googlesource.com'
             '/chromium/src/+/master/docs/testing/web_platform_tests.md\n\n'
             'NOAUTOREVERT=true\n'
-            'No-Export: true')
+            'No-Export: true\n'
+            'Cq-Include-Trybots: luci.chromium.try:linux-wpt-identity-fyi-rel,'
+            'linux-wpt-payments-fyi-rel')
         self.assertEqual(host.executive.calls,
                          [['git', 'log', '-1', '--format=%B']])