inspector-protocol/performance-timeline/largest-contentful-paint.js is flaky

TBR=caseq@chromium.org

Bug: 1164469
Change-Id: I28d850db9a5664ee168906c4d793a4751a670c28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626655Reviewed-by: Maxim Kolosovskiy  <kolos@chromium.org>
Commit-Queue: Maxim Kolosovskiy  <kolos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842999}

third_party/blink/web_tests/TestExpectations

@@ -71,6 +71,7 @@ crbug.com/1132260 http/tests/devtools/console/console-bad-stacktrace.js [ Pass F
 crbug.com/1132260 http/tests/devtools/console/console-uncaught-promise.js [ Pass Failure ]
 crbug.com/1132260 http/tests/devtools/tracing/timeline-network/timeline-network-resource-details.js [ Pass Failure ]
 crbug.com/1132260 inspector-protocol/page/frameAttachedStacktrace.js [ Pass Failure ]
+crbug.com/1164469 inspector-protocol/performance-timeline/largest-contentful-paint.js [ Pass Failure ]
 
 # With --enable-display-compositor-pixel-dump enabled by default, these three
 # tests fail. See crbug.com/887140 for more info.