Support for map literals in cps js emitter

tests/compiler/dart2js/js_backend_cps_ir_literals.dart

Index: tests/compiler/dart2js/js_backend_cps_ir_literals.dart
diff --git a/tests/compiler/dart2js/js_backend_cps_ir_literals.dart b/tests/compiler/dart2js/js_backend_cps_ir_literals.dart
index 514119a04491b609f25450a6d4293e44966e5a1f..02cfefe755d5f00dc5e2458e2d06eaa4d57fc54e 100644
--- a/tests/compiler/dart2js/js_backend_cps_ir_literals.dart
+++ b/tests/compiler/dart2js/js_backend_cps_ir_literals.dart
@@ -15,14 +15,20 @@ main() {
   print([1]);
   print([1, 2]);
   print([1, [1, 2]]);
+  print({});
+  print({1: 2});
+  print({[1, 2]: [3, 4]});
 }
 """,
-"""
+r"""
 function() {
   P.print([]);
   P.print([1]);
   P.print([1, 2]);
   P.print([1, [1, 2]]);
+  P.print(P.LinkedHashMap_LinkedHashMap$_empty());
+  P.print(P.LinkedHashMap_LinkedHashMap$_literal([1, 2]));
+  P.print(P.LinkedHashMap_LinkedHashMap$_literal([[1, 2], [3, 4]]));
   return null;
 }"""),
 ];