RFR: "null" makes the error by failing inference of type

[ShinyaYoshida]

Hi,

The type inference fails by "null":
-> null
(...)
+++++WRAP
package REPL;
import static REPL.$REPL2.*;
public class $REPL5 {
    public static Object do_it() throws Throwable {
        $1=null;;
               return $1;
    }
    public static <nulltype> $1;
}

-----
|  Error --
|  <identifier> expected
|  null;

Please review my patch.
webrev: http://cr.openjdk.java.net/~shinyafox/kulla/3/webrev.00/

Regards,
shinyafox
ShinyaYoshida