Reify type params on map literals

test/codegen_expected/language/string_interpolate2_test.js

 dart_library.library('language/string_interpolate2_test', null, /* Imports */[
   'dart_sdk',
   'expect'
 ], function load__string_interpolate2_test(exports, dart_sdk, expect) {
   'use strict';
   const core = dart_sdk.core;
   const _interceptors = dart_sdk._interceptors;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const expect$ = expect.expect;
@@ skipping 11 matching lines @@
       let s = dart.str`${i}`;
       expect$.Expect.equals("5", s);
       s = dart.str`fib(${i}) = ${fib[dartx.get](i)}`;
       expect$.Expect.equals("fib(5) = 8", s);
       i = 5;
       s = dart.str`${i} squared is ${dart.dcall(dart.fn(x => dart.dsend(x, '*', x), dynamicTodynamic()), i)}`;
       expect$.Expect.equals("5 squared is 25", s);
       expect$.Expect.equals("8", dart.str`${fib[dartx.length]}`);
       expect$.Expect.equals("8", dart.str`${fib[dartx.length]}`);
       expect$.Expect.equals("8", dart.str`${fib[dartx.length]}`);
-      let map = dart.map({red: 1, green: 2, blue: 3});
+      let map = dart.map({red: 1, green: 2, blue: 3}, core.String, core.int);
       s = dart.str`green has value ${map[dartx.get]("green")}`;
       expect$.Expect.equals("green has value 2", s);
       i = 0;
       function b() {
         return dart.str`${++i}`;
       }
       dart.fn(b, VoidTodynamic());
       s = dart.str`aaa ${dart.str`bbb ${b()} bbb`} aaa ${b()}`;
       expect$.Expect.equals("aaa bbb 1 bbb aaa 2", s);
       s = dart.str`a ${dart.fn(() => dart.str`b ${dart.fn(() => "c", VoidToString())()}`, VoidToString())()} d`;
       expect$.Expect.equals("a b c d", s);
     }
   };
   dart.setSignature(string_interpolate2_test.StringInterpolate2Test, {
     statics: () => ({testMain: dart.definiteFunctionType(dart.void, [])}),
     names: ['testMain']
   });
   string_interpolate2_test.StringInterpolate2Test.F1 = null;
   string_interpolate2_test.main = function() {
     string_interpolate2_test.StringInterpolate2Test.testMain();
   };
   dart.fn(string_interpolate2_test.main, VoidTodynamic());
   // Exports:
   exports.string_interpolate2_test = string_interpolate2_test;
 });