additional/pattern.js: Don't use exec() or test() here

In some cases, this code will not work correctly. Calling these methods on the same RegExp, will start checking from the end of the previous comparison.

src/additional/pattern.js

@@ -18,5 +18,5 @@ $.validator.addMethod( "pattern", function( value, element, param ) {
 	if ( typeof param === "string" ) {
 		param = new RegExp( "^(?:" + param + ")$" );
 	}
-	return param.test( value );
+	return value.match( param ) !== null;
 }, "Invalid format." );