[sheriff] Disable flaky autofill test on Android P emulator bots

AutofillAssistantTriggerScriptIntegrationTest#dontShowOnboardingIfAcceptedInDifferentTab
is failing on builder "android-pie-x86-rel".

Bug: 1163913
Change-Id: I93af1fee346650a370b28810111cbce51e860918
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2614782
Auto-Submit: Alex Ilin <alexilin@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841075}

testing/buildbot/filters/android.emulator_p.chrome_public_test_apk.filter

@@ -121,3 +121,6 @@
 
 # crbug.com/1159805
 -org.chromium.chrome.browser.customtabs.DetachedResourceRequestTest.testRepeatedIntents
+
+# crbug.com/1163913
+-org.chromium.chrome.browser.autofill_assistant.AutofillAssistantTriggerScriptIntegrationTest.dontShowOnboardingIfAcceptedInDifferentTab