script: Implement deprecated CSSStyleSheet members (#36313)

Implements `rules`, `addRule()` and `removeRule()` for `CSSStyleSheet`.
https://drafts.csswg.org/cssom/#legacy-css-style-sheet-members

This is part of #36162

Testing:
- `/css/css-cascade/at-scope-parsing.html`
- `/css/css-conditional/at-supports-whitespace.html`
- `/css/css-nesting/invalidation-004.html`
- `/css/css-nesting/parsing.html`
- `/css/css-nesting/serialize-group-rules-with-decls.html`
- `/css/css-syntax/custom-property-rule-ambiguity.html`
- `/css/css-syntax/invalid-nested-rules.html`
- `/css/css-syntax/trailing-braces.html`
- `/css/css-syntax/var-with-blocks.html`
- `/css/css-transitions/parsing/starting-style-parsing.html`
- `/css/cssom/CSSStyleSheet.html`
- `/css/cssom/idlharness.html`
- `/css/cssom/insertRule-across-context.html`

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

tests/wpt/meta/css/cssom/CSSStyleSheet.html.ini

@@ -1,25 +0,0 @@
-[CSSStyleSheet.html]
-  [addRule with no argument adds "undefined" selector]
-    expected: FAIL
-
-  [removeRule on empty style sheet throws]
-    expected: FAIL
-
-  [cssRules and rules are the same object]
-    expected: FAIL
-
-  [addRule with index greater than length throws]
-    expected: FAIL
-
-  [addRule with #foo selectors]
-    expected: FAIL
-
-  [removeRule(1)]
-    expected: FAIL
-
-  [removeRule with no argument removes first rule]
-    expected: FAIL
-
-  [addRule with @media rule]
-    expected: FAIL
-

tests/wpt/meta/css/cssom/idlharness.html.ini

@@ -53,9 +53,6 @@
   [SVGStyleElement interface: attribute sheet]
     expected: FAIL
 
-  [CSSStyleSheet interface: attribute rules]
-    expected: FAIL
-
   [CSSStyleDeclaration interface: sheet.cssRules[2\].cssRules[0\].style must inherit property "setProperty(CSSOMString, CSSOMString, optional CSSOMString)" with the proper type]
     expected: FAIL
 
@@ -101,9 +98,6 @@
   [CSSStyleDeclaration interface: svg_element.style must inherit property "cssFloat" with the proper type]
     expected: FAIL
 
-  [CSSStyleSheet interface: calling addRule(optional DOMString, optional DOMString, optional unsigned long) on sheet with too few arguments must throw TypeError]
-    expected: FAIL
-
   [CSSStyleDeclaration must be primary interface of sheet.cssRules[2\].cssRules[0\].style]
     expected: FAIL
 
@@ -161,9 +155,6 @@
   [CSSPageRule interface: existence and properties of interface prototype object's @@unscopables property]
     expected: FAIL
 
-  [CSSStyleSheet interface: operation addRule(optional DOMString, optional DOMString, optional unsigned long)]
-    expected: FAIL
-
   [CSSRule interface: sheet.cssRules[1\] must inherit property "parentRule" with the proper type]
     expected: FAIL
 
@@ -173,9 +164,6 @@
   [CSSPageRule interface: existence and properties of interface object]
     expected: FAIL
 
-  [CSSStyleSheet interface: sheet must inherit property "rules" with the proper type]
-    expected: FAIL
-
   [CSSPageRule must be primary interface of sheet.cssRules[2\]]
     expected: FAIL
 
@@ -230,9 +218,6 @@
   [CSSPageRule interface: sheet.cssRules[2\] must inherit property "selectorText" with the proper type]
     expected: FAIL
 
-  [CSSStyleSheet interface: sheet must inherit property "addRule(optional DOMString, optional DOMString, optional unsigned long)" with the proper type]
-    expected: FAIL
-
   [CSSMarginRule interface: existence and properties of interface prototype object's @@unscopables property]
     expected: FAIL
 
@@ -284,9 +269,6 @@
   [CSSStyleDeclaration interface: sheet.cssRules[2\].style must inherit property "cssText" with the proper type]
     expected: FAIL
 
-  [CSSStyleSheet interface: operation removeRule(optional unsigned long)]
-    expected: FAIL
-
   [Stringification of sheet.cssRules[4\]]
     expected: FAIL
 
@@ -347,9 +329,6 @@
   [CSSRule interface: sheet.cssRules[4\] must inherit property "cssText" with the proper type]
     expected: FAIL
 
-  [CSSStyleSheet interface: sheet must inherit property "removeRule(optional unsigned long)" with the proper type]
-    expected: FAIL
-
   [CSSMarginRule interface: existence and properties of interface prototype object's "constructor" property]
     expected: FAIL
 
@@ -407,9 +386,6 @@
   [CSSMarginRule interface: attribute style]
     expected: FAIL
 
-  [CSSStyleSheet interface: calling removeRule(optional unsigned long) on sheet with too few arguments must throw TypeError]
-    expected: FAIL
-
   [CSSStyleDeclaration interface: sheet.cssRules[2\].style must inherit property "getPropertyValue(CSSOMString)" with the proper type]
     expected: FAIL
 

tests/wpt/meta/css/cssom/insertRule-across-context.html.ini

@@ -1,6 +1,3 @@
 [insertRule-across-context.html]
-  [The constructor of inserted rule object must be from iframe]
-    expected: FAIL
-
   [The constructor of inserted rule object must be from iframe for new CSSStyleSheet()]
     expected: FAIL