update tests to include empty reciever case

Author: erik-krogh

javascript/ql/test/query-tests/Statements/IgnoreArrayResult/tst.js

@@ -6,4 +6,6 @@ arr.concat(arr); // NOT OK!
 
 console.log(arr.concat([1,2,3]));
 
-({concat: Array.prototype.concat}.concat(arr));
+({concat: Array.prototype.concat}.concat(arr));
+
+[].concat([1,2,3]);