WPT import https://crrev.com/c/1395981 introduced new failures in external/wpt/css/css-backgrounds:

List of new failures:
external/wpt/css/css-backgrounds/border-image-calc.html [ Failure ]

This import contains upstream changes from 71e901cf4534417abfabe4d77a317817f5cc09db to b32f1fa918a299f0e0c1addb70202734a8c6c9c0:
Handle calc() on border-image-width correctly.: https://github.com/web-platform-tests/wpt/commit/b32f1fa918a299f0e0c1addb70202734a8c6c9c0 [affecting this directory]
webdriver: re-enable test_maximize_when_resized_to_max_size: https://github.com/web-platform-tests/wpt/commit/677e47e1abbfd7967ae67b7395692e65dd70cabe
Give a better warning when no tests can be found in the specified path: https://github.com/web-platform-tests/wpt/commit/cd0ede7ec095dd10b53f6dfb0c794a94b02fa644
[IndexedDB]: Add commit check to aborting txns.: https://github.com/web-platform-tests/wpt/commit/6d9079e341f777ae47b2f39c9d116bfc77d141e2