Tests/LibWeb: Enable some tests relying on "reftest-wait"

Author: https://github.com/kalenikaliaksandr
Commit: 31da70bbfc
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3989
Reviewed-by: https://github.com/gmta ✅

Tests/LibWeb/TestConfig.ini

@@ -157,15 +157,6 @@ Text/input/wpt-import/css/css-backgrounds/animations/discrete-no-interpolation.h
 ; https://github.com/LadybirdBrowser/ladybird/issues/2900
 Text/input/ShadowDOM/css-hover-shadow-dom.html
 
-; WPT ref tests that are flaky, probably due to not supporting class="reftest-wait"
-; https://github.com/LadybirdBrowser/ladybird/issues/3984
-Ref/input/wpt-import/css/css-contain/contain-layout-020.html
-Ref/input/wpt-import/css/css-contain/contain-paint-050.html
-Ref/input/wpt-import/css/css-contain/contain-paint-change-opacity.html
-Ref/input/wpt-import/css/css-lists/list-style-type-string-004.html
-Ref/input/wpt-import/css/css-transforms/individual-transform/stacking-context-001.html
-Ref/input/wpt-import/png/apng/fDAT-inherits-cICP.html
-
 ; Test is flaky on CI, as navigationStart time is not set according to spec.
 Text/input/wpt-import/user-timing/measure_associated_with_navigation_timing.html
 
@@ -313,3 +304,6 @@ Text/input/wpt-import/html/syntax/parsing/html5lib_webkit02-write_single.html
 
 ; Inconsistently crashes because we haven't figured invalidation for CSS containment
 Crash/wpt-import/css/css-contain/contain-style-remove-element-crash.html
+Ref/input/wpt-import/css/css-contain/contain-layout-020.html
+Ref/input/wpt-import/css/css-contain/contain-paint-050.html
+Ref/input/wpt-import/css/css-contain/contain-paint-change-opacity.html