Skip virtual/threaded/fast/scrolling on SPv2

TBR=wangxianzhu@chromium.org

Bug: 841567
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I9bca44365295cd5ca2d41175a87f8ef07952dedd
Reviewed-on: https://chromium-review.googlesource.com/1055825
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558005}

third_party/WebKit/LayoutTests/FlagExpectations/enable-slimming-paint-v2

@@ -100,6 +100,7 @@ Bug(none) virtual/without-smil/ [ Skip ]
 Bug(none) virtual/blink-gen-property-trees/ [ Skip ]
 
 crbug.com/778875 virtual/threaded/fast/animationworklet/ [ Skip ]
+crbug.com/841567 virtual/threaded/fast/scrolling [ Skip ]
 
 # Fail on SPv1, but succeed on SPv2
 crbug.com/472330 fast/borders/border-image-outset-split-inline-vertical-lr.html [ Pass ]