Reify type params on map literals

test/codegen_expected/language/map_literal1_test_none_multi.js

 dart_library.library('language/map_literal1_test_none_multi', null, /* Imports */[
   'dart_sdk'
 ], function load__map_literal1_test_none_multi(exports, dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const map_literal1_test_none_multi = Object.create(null);
   let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
   let const$;
   map_literal1_test_none_multi.main = function() {
-    let m = const$ || (const$ = dart.const(dart.map({a: 0})));
+    let m = const$ || (const$ = dart.const(dart.map({a: 0}, core.String, core.int)));
   };
   dart.fn(map_literal1_test_none_multi.main, VoidTodynamic());
   // Exports:
   exports.map_literal1_test_none_multi = map_literal1_test_none_multi;
 });