All: Remove uses of jQuery.proxy()

Ref #15160
Closes gh-1813

Author: scottgonzalez

demos/autocomplete/combobox.html

@@ -48,7 +48,7 @@
 					.autocomplete({
 						delay: 0,
 						minLength: 0,
-						source: $.proxy( this, "_source" )
+						source: this._source.bind( this )
 					})
 					.tooltip({
 						classes: {

ui/widgets/autocomplete.js

@@ -447,7 +447,7 @@ $.widget( "ui.autocomplete", {
 	_response: function() {
 		var index = ++this.requestIndex;
 
-		return $.proxy( function( content ) {
+		return function( content ) {
 			if ( index === this.requestIndex ) {
 				this.__response( content );
 			}
@@ -456,7 +456,7 @@ $.widget( "ui.autocomplete", {
 			if ( !this.pending ) {
 				this._removeClass( "ui-autocomplete-loading" );
 			}
-		}, this );
+		}.bind( this );
 	},
 
 	__response: function( content ) {