[ChromeDriver] Re-enable SessionHandlingTests for integration

The condition causing these two tests to fail no longer exists,
thus re-enabling them.

Bug: 851721
Change-Id: I4a21c41fbe35af45c45b2e215ae0ed54495004ad
Reviewed-on: https://chromium-review.googlesource.com/1115209Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570432}

chrome/test/chromedriver/test/run_py_tests.py

@@ -152,10 +152,6 @@ _INTEGRATION_NEGATIVE_FILTER = [
     # RemoteBrowserTest requires extra setup. TODO(johnchen@chromium.org):
     # Modify the test so it runs correctly as isolated test.
     'RemoteBrowserTest.*',
-    # These two SessionHandlingTest tests fail on the Mac 10.10 bot.
-    # See http://crbug.com/851721
-    'SessionHandlingTest.testGetSessions',
-    'SessionHandlingTest.testQuitASessionMoreThanOnce',
 ]