WPT import https://crrev.com/c/1152529 introduced new failures in external/wpt/css:

List of new failures:
external/wpt/css/css-animations/idlharness.html new failing tests: https://crrev.com/c/1152529/4/third_party/WebKit/LayoutTests/external/wpt/css/css-animations/idlharness-expected.txt
external/wpt/css/css-transitions/idlharness.html new failing tests: https://crrev.com/c/1152529/4/third_party/WebKit/LayoutTests/external/wpt/css/css-transitions/idlharness-expected.txt

This import contains upstream changes from efef417d9f9ceb9016f682c3aa523d31405e1238 to 849352db27a750476f5cbd42a279025884948400:
Don't reset pending tasks when setting the target effect to null (#12194): https://github.com/web-platform-tests/wpt/commit/849352db27a750476f5cbd42a279025884948400
Add the webgl1 IDL file + test (#12196): https://github.com/web-platform-tests/wpt/commit/8263509514ae6aec4e63d2bd2c787a862d8c361a
Use navigation start time in the case where the refresh driver's time stamp is behind from the start time to avoid negative timelime time at the very beginning of document load.: https://github.com/web-platform-tests/wpt/commit/ee1ce48e3834f99db45cef18c41b6e5b189486fa
Fix manifest paths obtained from the file system: https://github.com/web-platform-tests/wpt/commit/bdae4c34e7490ddc5f16c5718d445cd0af159941
Added a way to specify aliases using command line.: https://github.com/web-platform-tests/wpt/commit/3f67724a2abefcbdf43e8797579a2e2c2c6a40f8
<input>: INPUT element with unknown type attribute value should be rendered same as <input type=text>.: https://github.com/web-platform-tests/wpt/commit/65dd8395f9303543a90abbb58ef31be6fba3a33e
Created new interface and class TrustedTypePolicy: https://github.com/web-platform-tests/wpt/commit/2a5fed3d1f1691b8b02b6ee645c1ea00143d6c57
url: DecodeURLEscapeSequences() should not apply UTF-8 and isomorphic encoding to a single input.: https://github.com/web-platform-tests/wpt/commit/c54b4511852cd7acdb0aed4108f38487ab95418f
[idlharness.js] Add inheritor as dep for includes (#12165): https://github.com/web-platform-tests/wpt/commit/2fe1bdb04188923e8933161a46e71718f33f8fdb [affecting this directory]