Check in codegen test expectations.

test/codegen/expect/language/interface_inherit_field_test.js

+dart_library.library('language/interface_inherit_field_test', null, /* Imports */[
+  'dart_sdk'
+], function load__interface_inherit_field_test(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const interface_inherit_field_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  interface_inherit_field_test.IA = class IA extends core.Object {
+    new() {
+      this.foo = null;
+    }
+  };
+  interface_inherit_field_test.IB = class IB extends core.Object {
+    new() {
+      this.foo = null;
+    }
+  };
+  interface_inherit_field_test.IB[dart.implements] = () => [interface_inherit_field_test.IA];
+  const _f = Symbol('_f');
+  interface_inherit_field_test.B = class B extends core.Object {
+    new() {
+      this[_f] = 123;
+    }
+    get foo() {
+      return this[_f];
+    }
+  };
+  interface_inherit_field_test.B[dart.implements] = () => [interface_inherit_field_test.IB];
+  interface_inherit_field_test.main = function() {
+    let b = new interface_inherit_field_test.B();
+    core.print(dart.str`b.foo = ${b.foo}`);
+  };
+  dart.fn(interface_inherit_field_test.main, VoidTodynamic());
+  // Exports:
+  exports.interface_inherit_field_test = interface_inherit_field_test;
+});