Remove flakiness expectation for...

Remove flakiness expectation for paint/invalidation/selection/selection-partial-invalidation-between-blocks.html

It's no longer flaky:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=paint%2Finvalidation%2Fselection%2Fselection-partial-invalidation-between-blocks.html

TBR=yoichio@chromium.org

Bug: 774437
Change-Id: I40e82ad1c5cab68d9996961eba44394edf26ed7f
Reviewed-on: https://chromium-review.googlesource.com/1220171Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590423}

third_party/WebKit/LayoutTests/TestExpectations

@@ -4368,7 +4368,6 @@ crbug.com/773122 [ Win7 ] fast/text/whitespace/022.html [ Failure Pass ]
 crbug.com/773122 [ Win7 ] fast/text/word-break.html [ Failure Pass ]
 
 # Sheriff failures 2017-10-13
-crbug.com/774437 paint/invalidation/selection/selection-partial-invalidation-between-blocks.html [ Pass Failure ]
 crbug.com/774463 [ Win7 Debug ] fast/events/autoscroll-should-not-stop-on-keypress.html [ Failure Pass ]
 crbug.com/774463 [ Win7 Debug ] virtual/mouseevent_fractional/fast/events/autoscroll-should-not-stop-on-keypress.html [ Failure Pass ]
 crbug.com/774688 [ Mac ] fast/spatial-navigation/snav-container-white-space.html [ Pass Failure ]