Fixed JSON integers as strings not being parsed correctly.

Change-Id: If34aef46ef619e06de799cff14948b02e98da86d
Tested: on Linux.

src/idl_parser.cpp

@@ -974,6 +974,7 @@ CheckedError Parser::ParseSingleValue(Value &e) {
         assert(0);  // Shouldn't happen, we covered all types.
         e.constant = "0";
       }
+      NEXT();
     }
   } else {
     bool match = false;