[ChromeDriver] Disable failing tests on Waterfall on Windows build bot

Disabling failing tests testDownloadDirectoryOverridesExistingPreferences and
testExistingDevToolsPortFile on Waterfall on Windows build bot

Bug: 907608:chromedriver:2673
Change-Id: I74adcfa17f6349aa74805e6905fa630661ea4a9b
Reviewed-on: https://chromium-review.googlesource.com/c/1347613Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Artur Khachatryan <khachatryan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610254}

chrome/test/chromedriver/test/run_py_tests.py

@@ -122,6 +122,9 @@ _OS_SPECIFIC_FILTER = {}
 _OS_SPECIFIC_FILTER['win'] = [
     # https://bugs.chromium.org/p/chromedriver/issues/detail?id=299
     'ChromeLogPathCapabilityTest.testChromeLogPath',
+    # https://bugs.chromium.org/p/chromedriver/issues/detail?id=2673
+    'ChromeDownloadDirTest.testDownloadDirectoryOverridesExistingPreferences',
+    'LaunchDesktopTest.testExistingDevToolsPortFile',
 ]
 _OS_SPECIFIC_FILTER['linux'] = [
 ]