Auto merge of #23685 - saschanaz:scalenonuniform, r=paulrouget

Add DOMMatrix.prototype.scaleNonUniform

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Implements `scaleNonUniform()` [per the spec](https://drafts.fxtf.org/geometry/#dom-dommatrixreadonly-scalenonuniform).

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- [x] These changes fix #23683

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- [x] There are tests for these changes

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components/script/dom/webidls/DOMMatrixReadOnly.webidl

@@ -56,6 +56,8 @@ interface DOMMatrixReadOnly {
                     optional unrestricted double originX = 0,
                     optional unrestricted double originY = 0,
                     optional unrestricted double originZ = 0);
+    [NewObject] DOMMatrix scaleNonUniform(optional unrestricted double scaleX = 1,
+                                          optional unrestricted double scaleY = 1);
     DOMMatrix scale3d(optional unrestricted double scale = 1,
                       optional unrestricted double originX = 0,
                       optional unrestricted double originY = 0,