Re-enable repeating thead tests on Mac and Win

Bug: 636053
Change-Id: I9ed72d459d43f2a0113e4c46a496f6ecf65665d6
Reviewed-on: https://chromium-review.googlesource.com/593308Reviewed-by: Robert Hogan <robhogan@gmail.com>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Robert Hogan <robhogan@gmail.com>
Cr-Commit-Position: refs/heads/master@{#490936}

third_party/WebKit/LayoutTests/TestExpectations

@@ -699,9 +699,6 @@ crbug.com/518989 [ Mac ] external/wpt/css/css-writing-modes-3/writing-mode-verti
 # These performance-sensitive user-timing tests are flaky in debug on all platforms, and flaky on all configurations of windows.
 # See: crbug.com/567965, crbug.com/518992, and crbug.com/518993
 
-crbug.com/636053 [ Mac Win ] printing/thead-repeats-at-top-of-each-page-multiple-tables.html [ NeedsManualRebaseline ]
-crbug.com/636053 [ Mac Win ] virtual/threaded/printing/thead-repeats-at-top-of-each-page-multiple-tables.html [ NeedsManualRebaseline ]
-
 crbug.com/432129 html/marquee/marquee-scroll.html [ Failure Pass ]
 crbug.com/326139 crbug.com/390125 media/video-frame-accurate-seek.html [ Failure Pass ]
 crbug.com/248938 virtual/threaded/animations/stability/animation-iteration-event-destroy-renderer.html [ Pass Timeout ]