Datepicker Tests: use simulated events for focus and blur.(cherry picked from commit ab84e037ed)

tests/unit/datepicker/datepicker_options.js

@@ -114,7 +114,7 @@ asyncTest( "invocation", function() {
 
 				step2();
 			});
-		})[ 0 ].focus();
+		}).simulate( "focus" );
 	}
 
 	function step2() {

tests/unit/datepicker/datepicker_test_helpers.js

@@ -22,8 +22,8 @@ TestHelpers.datepicker = {
 		element.one( "blur", function(){
 			element.one( "focus", function(){
 				callback();
-			})[ 0 ].focus();
-		})[ 0 ].blur();
+			}).simulate( "focus" );
+		}).simulate( "blur" );
 	},
 	PROP_NAME: "datepicker"
 };