Disable testIFrame on windows

It is flakey on win bots.
http://build.chromium.org/p/chromium.win/builders/Win%207%20Tests%20x64%20%283%29/builds/15075
http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%282%29/builds/30300

TBR=achuith@chromium.org
NOTRY=true
BUG=394454

Review URL: https://codereview.chromium.org/406233002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284665 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/backends/chrome/inspector_runtime_unittest.py

@@ -35,7 +35,7 @@ class InspectorRuntimeTest(tab_test_case.TabTestCase):
     self._tab.ExecuteJavaScript('window')
 
   # TODO(achuith): Fix http://crbug.com/394454 on cros.
-  @decorators.Disabled('android', 'chromeos')
+  @decorators.Disabled('android', 'chromeos', 'win')
   def testIFrame(self):
     self.Navigate('host.html')