Some external/wpt/html/user-activation tests are flaky

They are flaky on many CQ bots, regardless of composite-after-paint:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=blink_web_tests%20(with%20patch)&tests=external%2Fwpt%2Fhtml%2Fuser-activation%2Fconsumption-crossorigin.sub.tentative.html%20external%2Fwpt%2Fhtml%2Fuser-activation%2Fnavigation-state-reset-crossorigin.sub.tentative.html%20%20external%2Fwpt%2Fhtml%2Fuser-activation%2Fpropagation-crossorigin.sub.tentative.html

Move the failure expectations from composite-after-paint into
TestExpectations.

TBR=mustaq@chromium.org

Bug: 1064422, 1066178, 1066190
Change-Id: Iffa9df6e6607f85772d65d2969e3d0964790fe30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2203276Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769050}

third_party/blink/web_tests/FlagExpectations/composite-after-paint

@@ -96,8 +96,3 @@ crbug.com/1047359 http/tests/subresource_filter/ad-highlight-frame-resized.html
 
 compositing/gestures/gesture-tapHighlight-composited-img.html [ Pass Failure ]
 http/tests/images/image-decode-in-frame.html [ Pass Failure ]
-
-# User Activation
-crbug.com/736415 external/wpt/html/user-activation/navigation-state-reset-crossorigin.sub.tentative.html [ Failure Timeout ]
-external/wpt/html/user-activation/consumption-crossorigin.sub.tentative.html [ Timeout ]
-external/wpt/html/user-activation/propagation-crossorigin.sub.tentative.html [ Timeout ]

third_party/blink/web_tests/TestExpectations

@@ -4650,8 +4650,10 @@ crbug.com/854910 [ Mac ] fast/scroll-behavior/smooth-scroll/track-scroll.html [
 crbug.com/855816 [ Win ] virtual/stable/http/tests/navigation/rename-subframe-goback.html [ Pass Timeout ]
 
 # User Activation
-crbug.com/736415 external/wpt/html/user-activation/navigation-state-reset-crossorigin.sub.tentative.html [ Failure ]
+crbug.com/736415 crbug.com/1066190 external/wpt/html/user-activation/navigation-state-reset-crossorigin.sub.tentative.html [ Failure Timeout ]
 crbug.com/736415 external/wpt/html/user-activation/navigation-state-reset-sameorigin.tentative.html [ Failure ]
+crbug.com/1066178 external/wpt/html/user-activation/consumption-crossorigin.sub.tentative.html [ Pass Timeout ]
+crbug.com/1064522 external/wpt/html/user-activation/propagation-crossorigin.sub.tentative.html [ Pass Timeout ]
 
 # Sheriff 2018-07-05
 crbug.com/860731 fast/scroll-snap/animate-fling-to-snap-points.html [ Failure Pass ]