fixes #616, statics on callable functions

test/codegen_expected/language/call_argument_inference_test.js

 dart_library.library('language/call_argument_inference_test', null, /* Imports */[
   'dart_sdk',
   'expect'
 ], function load__call_argument_inference_test(exports, dart_sdk, expect) {
   'use strict';
   const core = dart_sdk.core;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const expect$ = expect.expect;
   const call_argument_inference_test = Object.create(null);
   let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
   call_argument_inference_test.A = dart.callableClass(function A(...args) {
-    const self = this;
     function call(...args) {
-      return self.call.apply(self, args);
+      return call.call.apply(call, args);
     }
     call.__proto__ = this.__proto__;
     call.new.apply(call, args);
     return call;
   }, class A extends core.Object {
     call(a) {
       return typeof a == 'number';
     }
   });
   dart.setSignature(call_argument_inference_test.A, {
     methods: () => ({call: dart.definiteFunctionType(dart.dynamic, [dart.dynamic])})
   });
   call_argument_inference_test.main = function() {
     expect$.Expect.isTrue(new call_argument_inference_test.A().call(42));
     expect$.Expect.isFalse(dart.dcall(new call_argument_inference_test.A(), 'foo'));
   };
   dart.fn(call_argument_inference_test.main, VoidTodynamic());
   // Exports:
   exports.call_argument_inference_test = call_argument_inference_test;
 });