Revert "Disable flaky ChromeDriverTest"

This reverts commit 1748ac49.

Reason for revert: Cause of the flakiness has already been fixed

Original change's description:
> Disable flaky ChromeDriverTest
> 
> TBR: khachatryan@chromium.org
> Bug: 865842
> Change-Id: I33180c2c852a8da94cf735a1437eac3748203153
> Reviewed-on: https://chromium-review.googlesource.com/1151027
> Reviewed-by: Yoichi Osato <yoichio@chromium.org>
> Commit-Queue: Yoichi Osato <yoichio@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#578210}

TBR=yoichio@chromium.org

Change-Id: Ib630eb7748189190c9e49809f1730ca0ca5f04ec
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 865842
Reviewed-on: https://chromium-review.googlesource.com/1152307Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578457}

chrome/test/chromedriver/test/run_py_tests.py

@@ -80,9 +80,6 @@ _NEGATIVE_FILTER = [
     'MobileEmulationCapabilityTest.testClickElement',
     'MobileEmulationCapabilityTest.testNetworkConnectionTypeIsAppliedToAllTabs',
     'MobileEmulationCapabilityTest.testNetworkConnectionTypeIsAppliedToAllTabsImmediately',
-    # Flaky on Win. See http://crbug.com/865842.
-    'ChromeDriverTest.testCanClickInIframes',
-    'ChromeDriverTest.testMoveToElementAndClick'
 ]
 
 _VERSION_SPECIFIC_FILTER = {}