jQuery.ajax modified the passed-in object only to help test the code - this...

jQuery.ajax modified the passed-in object only to help test the code - this shouldn't occur. Fixes #5439.

src/ajax.js

@@ -194,7 +194,7 @@ jQuery.extend({
 	ajax: function( s ) {
 		// Extend the settings, but re-extend 's' so that it can be
 		// checked again later (in the test suite, specifically)
-		s = jQuery.extend(true, s, jQuery.extend(true, {}, jQuery.ajaxSettings, s));
+		s = jQuery.extend(true, {}, jQuery.ajaxSettings, s);
 		
 		var jsonp, status, data,
 			callbackContext = s.context || window,

test/unit/ajax.js

@@ -368,6 +368,10 @@ test("ajax cache", function () {
 	ok( jQuery.ajax({url: "data/text.php?name=David&_=tobereplaced555&washere=true", cache:false}), "test with 2 parameters surrounding _= one" );
 });
 
+/*
+ * Test disabled.
+ * The assertions expect that the passed-in object will be modified,
+ * which shouldn't be the case. Fixes #5439.
 test("global ajaxSettings", function() {
 	expect(2);
 
@@ -389,6 +393,7 @@ test("global ajaxSettings", function() {
 
 	jQuery.ajaxSettings = tmp;
 });
+*/
 
 test("load(String)", function() {
 	expect(1);