[blink_perf.css] Disable failing test CustomPropertiesVarAlias.html

NOTRY=true
TBR=nednguyen@google.com
CC=andruud@chromium.org,futhark@chromium.org

Bug: 891878
Change-Id: I52e2b98faee15e90b2d6dbb71f1d572fa64c5ab7
Reviewed-on: https://chromium-review.googlesource.com/c/1259617
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596373}
1 file changed