Disable UkmBrowserTest.SingleSyncSignoutCheck.

The test was re-enabled in crrev/c/crrev/c/2350231; however, fixing the
original error uncovered an additional one:

[FATAL:network_context.mojom.cc(9680)] Check failed: !connected. \
NetworkContext::ClearHttpCacheCallback was destroyed without first \
either being run or its corresponding binding being closed. It is an \
error to drop response callbacks which still correspond to an open \
interface pipe.

Bug: 1096047
Change-Id: Ia4702463ab41fba49827baa93b9f15b74af21125
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2354290
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797711}

chrome/browser/metrics/ukm_browsertest.cc

@@ -972,10 +972,13 @@ IN_PROC_BROWSER_TEST_F(UkmBrowserTest, LogsOpenerSource) {
 
 // ChromeOS doesn't have the concept of sign-out so this test doesn't make sense
 // there.
-#if !defined(OS_CHROMEOS)
+//
+// Flaky on Android: https://crbug.com/1096047.
+//
 // Make sure that UKM is disabled when the profile signs out of Sync.
 // Keep in sync with testSingleSyncSignout in ios/chrome/browser/metrics/
 // ukm_egtest.mm.
+#if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
 IN_PROC_BROWSER_TEST_F(UkmBrowserTest, SingleSyncSignoutCheck) {
   ukm::UkmTestHelper ukm_test_helper(GetUkmService());
   MetricsConsentOverride metrics_consent(true);
@@ -996,7 +999,7 @@ IN_PROC_BROWSER_TEST_F(UkmBrowserTest, SingleSyncSignoutCheck) {
   harness->service()->GetUserSettings()->SetSyncRequested(false);
   ClosePlatformBrowser(browser);
 }
-#endif  // !defined(OS_CHROMEOS)
+#endif  // !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
 
 // ChromeOS doesn't have the concept of sign-out so this test doesn't make sense
 // there. Android doesn't have multiple profiles.