Sync WPT with upstream (06-07-2025) (#37901)

Automated downstream sync of changes from upstream as of 06-07-2025
[no-wpt-sync]

---------

Signed-off-by: WPT Sync Bot <ghbot+wpt-sync@servo.org>
Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
Co-authored-by: sagudev <16504129+sagudev@users.noreply.github.com>

tests/wpt/meta/css/css-mixins/basic.html.ini

@@ -0,0 +1,3 @@
+[basic.html]
+  [CSS Mixins: Basic test]
+    expected: FAIL

tests/wpt/meta/css/css-mixins/contents-rule.html.ini

@@ -0,0 +1,15 @@
+[contents-rule.html]
+  [Simple @contents with no fallback]
+    expected: FAIL
+
+  [Implicit semicolon after @contents, at end of block]
+    expected: FAIL
+
+  [Block in @apply overrides fallback]
+    expected: FAIL
+
+  [Fallback is used if @apply has no block]
+    expected: FAIL
+
+  [@contents is ignored if there is no @contents parameter]
+    expected: FAIL

tests/wpt/meta/css/css-mixins/cross-stylesheet.html.ini

@@ -0,0 +1,3 @@
+[cross-stylesheet.html]
+  [CSS Mixins: Mixin from another stylesheet]
+    expected: FAIL

tests/wpt/meta/css/css-mixins/declarations.html.ini

@@ -0,0 +1,3 @@
+[declarations.html]
+  [CSS Mixins: Declarations directly in mixin]
+    expected: FAIL

tests/wpt/meta/css/css-mixins/mixins-including-mixins.html.ini

@@ -0,0 +1,3 @@
+[mixins-including-mixins.html]
+  [CSS Mixins: Mixins depending on other mixins]
+    expected: FAIL

tests/wpt/meta/css/css-mixins/shadow-dom.html.ini

@@ -0,0 +1,9 @@
+[shadow-dom.html]
+  [Style in shadow DOM should have access to outside non-adopted mixins]
+    expected: FAIL
+
+  [Style in shadow DOM should have access to inside mixins]
+    expected: FAIL
+
+  [Style in shadow DOM should have access to mixins from adopted stylesheets]
+    expected: FAIL