Tests: Disable the ":lang respects escaped backslashes" test

Firefox 114+ no longer match on backslashes in `:lang()`, even when escaped.
It is an intentional change as `:lang()` parameters are supposed to be valid
BCP 47 strings. Therefore, we won't attempt to patch it.
We'll keep this test here until other browsers match the behavior.

Ref jquery/jquery#5271
Ref jquery/jquery#5277
Ref https://bugzilla.mozilla.org/show_bug.cgi?id=1839747#c1
Ref w3c/csswg-drafts#8720 (comment)

test/unit/selector.js

@@ -1246,7 +1246,7 @@ QUnit.test( "pseudo - :target and :root", function( assert ) {
 } );
 
 QUnit.test( "pseudo - :lang", function( assert ) {
-	assert.expect( 105 );
+	assert.expect( 104 );
 
 	var docElem = document.documentElement,
 		docXmlLang = docElem.getAttribute( "xml:lang" ),
@@ -1319,8 +1319,17 @@ QUnit.test( "pseudo - :lang", function( assert ) {
 	anchor.parentNode.lang = "ara";
 	anchor.lang = "ara\\b";
 	assert.deepEqual( Sizzle( ":lang(ara\\b)", foo ), [], ":lang respects backslashes" );
-	assert.deepEqual( Sizzle( ":lang(ara\\\\b)", foo ), [ anchor ],
-		":lang respects escaped backslashes" );
+
+	// Support: Firefox 114+
+	// Firefox 114+ no longer match on backslashes in `:lang()`, even when escaped.
+	// It is an intentional change as `:lang()` parameters are supposed to be valid
+	// BCP 47 strings. Therefore, we won't attempt to patch it.
+	// We'll keep this test here until other browsers match the behavior.
+	// See https://bugzilla.mozilla.org/show_bug.cgi?id=1839747#c1
+	// See https://github.com/w3c/csswg-drafts/issues/8720#issuecomment-1509242961
+	// assert.deepEqual( Sizzle( ":lang(ara\\\\b)", foo ), [ anchor ],
+	// 	":lang respects escaped backslashes" );
+
 	assert.throws( function() {
 		Sizzle.call( null, "#qunit-fixture:lang(c++)" );
 	}, function( e ) {