Check in codegen test expectations.

test/codegen/expect/language/external_test_20_multi.js

+dart_library.library('language/external_test_20_multi', null, /* Imports */[
+  'dart_sdk'
+], function load__external_test_20_multi(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const external_test_20_multi = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  external_test_20_multi.Bar = class Bar extends core.Object {
+    new(val) {
+    }
+  };
+  dart.setSignature(external_test_20_multi.Bar, {
+    constructors: () => ({new: dart.definiteFunctionType(external_test_20_multi.Bar, [dart.dynamic])})
+  });
+  external_test_20_multi.Foo = class Foo extends core.Object {
+    f() {}
+    new() {
+      this.x = 0;
+    }
+  };
+  dart.defineNamedConstructor(external_test_20_multi.Foo, 'n20');
+  dart.setSignature(external_test_20_multi.Foo, {
+    constructors: () => ({
+      new: dart.definiteFunctionType(external_test_20_multi.Foo, []),
+      n20: dart.definiteFunctionType(external_test_20_multi.Foo, [dart.dynamic])
+    }),
+    methods: () => ({f: dart.definiteFunctionType(dart.dynamic, [])})
+  });
+  external_test_20_multi.main = function() {
+    let foo = new external_test_20_multi.Foo();
+    new external_test_20_multi.Foo.n20(1);
+  };
+  dart.fn(external_test_20_multi.main, VoidTodynamic());
+  // Exports:
+  exports.external_test_20_multi = external_test_20_multi;
+});