fix "unresolved names" code generation

pkg/dev_compiler/test/codegen_expected/unresolved_names.js

+define(['dart_sdk'], function(dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const unresolved_names = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.fnType(dart.dynamic, [])))();
+  unresolved_names.C = class C extends core.Object {};
+  unresolved_names.main = function() {
+    new (dart.throw("compile error: unresolved constructor: " + "dynamic" + "." + "<unnamed>"))();
+    new (dart.throw("compile error: unresolved constructor: " + "C" + "." + "bar"))();
+    core.print(dart.throw("compile error: unresolved identifier: " + "baz"));
+    core.print(dart.dload(unresolved_names.C, 'quux'));
+  };
+  dart.fn(unresolved_names.main, VoidTodynamic());
+  dart.trackLibraries("unresolved_names", {
+    "unresolved_names.dart": unresolved_names
+  }, null);
+  // Exports:
+  return {
+    unresolved_names: unresolved_names
+  };
+});