This feature is part of --enable-experimental-web-platform-features, so
it should be enabled on all tests.
This causes some new failures, but mostly it's because the tests were
timing out instead of running the failing subtests.
This is part of #36315
Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Most tests were only being run for layout-2013, not for layout-2020.
This wasn't great since layout-2020 is now the default.
So this patch unifies the lists of included tests for both layouts.
For layout-2013 this implies adding css/css-content/, css/css-logical/
and css/css-masking/clip/.
For layout-2020 this implies adding several additional css tests, and
also tests like dom/, js/, html/, etc.