Disable flaky AutofillAssistantChromeTabIntegrationTest

#newTabButtonHidesAndRecoversOnboarding is flaky (like a few other
tests in the same suite)

Tbr: arbesser@google.com
Bug: 1157339
Change-Id: I8122ac9d6fc937d4e8b2c505b6aaa769605f1d57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593098Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837085}

chrome/android/features/autofill_assistant/javatests/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantChromeTabIntegrationTest.java

@@ -612,6 +612,7 @@ public class AutofillAssistantChromeTabIntegrationTest {
 
     @Test
     @MediumTest
+    @DisabledTest(message = "Flaky - https://crbug.com/1157339")
     // Restricted to phones due to https://crbug.com/429671
     @Restriction(UiRestriction.RESTRICTION_TYPE_PHONE)
     public void newTabButtonHidesAndRecoversOnboarding() {