Improve Function constructor argument handling.

For the Function constructor it is possible to pass the
name of the function arguments in one or more strings, and
each argument name should be separated with a comma.

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.u-szeged@partner.samsung.com

tests/jerry/function-construct.js

@@ -62,6 +62,15 @@ for (i = 1; i < 10; i ++)
   }
 }
 
+var f = new Function ("a,b", "c", "return a + b + c;");
+assert (f (1,2,3) === 6);
+
+f = new Function ("a,b", "c,d", "return a + b + c + d;");
+assert (f (1,2,3,4) === 10);
+
+f = new Function ("a" , "b", "c,d", "return a + b + c + d;");
+assert (f (1,2,3,4) === 10);
+
 try
 {
   new Function ({