Disable failing background-attachment-local-scrolling.htm

TBR=pdr@chromium.org,wangxianzhu@chromium.org

Bug: 1166540,1046544
Change-Id: I37ae96bb63da98c90fd85875742b5c76abf34e7b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628948Reviewed-by: Andy Paicu <andypaicu@chromium.org>
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843444}

third_party/blink/web_tests/TestExpectations

@@ -5842,3 +5842,6 @@ crbug.com/1163793 http/tests/inspector-protocol/page/page-events-associated.js [
 
 # Sheriff 2021-01-13
 crbug.com/1164459 [ Mac10.15 ] external/wpt/preload/download-resources.html [ Pass Failure ]
+
+# Sheriff 2021-01-14
+crbug.com/1166540 [ Mac ] ietestcenter/css3/bordersbackgrounds/background-attachment-local-scrolling.htm [ Pass Failure ]