Enable test DeviceCloudPolicyManagerChromeOSEnrollmentTest.UnregisterSucceeds

The flakiness of the test was fixed in the CL that fixed
DeviceCloudPolicyManagerChromeOSEnrollmentTest.Success

Bug: 1014318
Test: DeviceCloudPolicyManagerChromeOSEnrollmentTest.UnregisterSucceeds
Change-Id: I5b89b3dc1eb63a223093832c2ff8ec696be4d668
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1939413Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Michael Ershov <miersh@google.com>
Cr-Commit-Position: refs/heads/master@{#719566}

chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos_unittest.cc

@@ -823,9 +823,7 @@ TEST_P(DeviceCloudPolicyManagerChromeOSEnrollmentTest, LoadError) {
   EXPECT_EQ(CloudPolicyStore::STATUS_LOAD_ERROR, status_.store_status());
 }
 
-// Flaky. https://crbug.com/1014318
-TEST_P(DeviceCloudPolicyManagerChromeOSEnrollmentTest,
-       DISABLED_UnregisterSucceeds) {
+TEST_P(DeviceCloudPolicyManagerChromeOSEnrollmentTest, UnregisterSucceeds) {
   // Enroll first.
   RunTest();
   ExpectSuccessfulEnrollment();