Check in codegen test expectations.

test/codegen/expect/language/field3a_negative_test.js

+dart_library.library('language/field3a_negative_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__field3a_negative_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const field3a_negative_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  field3a_negative_test.C = class C extends core.Object {
+    new() {
+      this.a = null;
+    }
+  };
+  field3a_negative_test.main = function() {
+    let val = new field3a_negative_test.C();
+    expect$.Expect.equals(val.a, 0);
+  };
+  dart.fn(field3a_negative_test.main, VoidTodynamic());
+  // Exports:
+  exports.field3a_negative_test = field3a_negative_test;
+});