Reify type params on map literals

test/codegen_expected/language/list_tracer_in_map_test.js

 dart_library.library('language/list_tracer_in_map_test', null, /* Imports */[
   'dart_sdk'
 ], function load__list_tracer_in_map_test(exports, dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const _interceptors = dart_sdk._interceptors;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const list_tracer_in_map_test = Object.create(null);
   let JSArrayOfint = () => (JSArrayOfint = dart.constFn(_interceptors.JSArray$(core.int)))();
+  let ListOfint = () => (ListOfint = dart.constFn(core.List$(core.int)))();
   let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
   dart.defineLazy(list_tracer_in_map_test, {
     get b() {
       return JSArrayOfint().of([42]);
     },
     set b(_) {}
   });
   dart.defineLazy(list_tracer_in_map_test, {
     get a() {
-      return dart.map({foo: list_tracer_in_map_test.b});
+      return dart.map({foo: list_tracer_in_map_test.b}, core.String, ListOfint());
     },
     set a(_) {}
   });
   list_tracer_in_map_test.main = function() {
     list_tracer_in_map_test.a[dartx.get]('foo')[dartx.clear]();
     if (list_tracer_in_map_test.b[dartx.length] != 0) dart.throw('Test failed');
   };
   dart.fn(list_tracer_in_map_test.main, VoidTodynamic());
   // Exports:
   exports.list_tracer_in_map_test = list_tracer_in_map_test;
 });