[sheriff] Disable It2MeHostTest.RelayPolicy_DisabledTransitionCausesDisconnect

The test is flaky on multiple platforms.

TBR=joedow@chromium.org

Bug: 1126973
Change-Id: I4584e882fa96a9e442f01ad975c3acf92c406aa5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418977Reviewed-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808402}

remoting/host/it2me/it2me_host_unittest.cc

@@ -489,7 +489,8 @@ TEST_F(It2MeHostTest, RelayPolicy_Disabled) {
   ASSERT_EQ(It2MeHostState::kDisconnected, last_host_state_);
 }
 
-TEST_F(It2MeHostTest, RelayPolicy_DisabledTransitionCausesDisconnect) {
+// TODO(crbug.com/1126973): Flaky test.
+TEST_F(It2MeHostTest, DISABLED_RelayPolicy_DisabledTransitionCausesDisconnect) {
   StartHost();
   ASSERT_EQ(It2MeHostState::kReceivedAccessCode, last_host_state_);