Insert checks before deferred calls and accesses.

tests/compiler/dart2js_extra/deferred/deferred_function_test.dart

Index: tests/compiler/dart2js_extra/deferred/deferred_function_test.dart
diff --git a/tests/compiler/dart2js_extra/deferred/deferred_function_test.dart b/tests/compiler/dart2js_extra/deferred/deferred_function_test.dart
index aad0c5739eb49cf49f602cee8e777f464ae5d2eb..e6f7f8827c8153204f08defedf3f41db687ef94d 100644
--- a/tests/compiler/dart2js_extra/deferred/deferred_function_test.dart
+++ b/tests/compiler/dart2js_extra/deferred/deferred_function_test.dart
@@ -14,18 +14,15 @@ import 'dart:async';
 
 const lazy = const DeferredLibrary('deferred_function_library');
 
-isNoSuchMethodError(e) => e is NoSuchMethodError;
+isError(e) => e is Error;
 
 readFoo() {
-  // TODO(ahe): There is a problem with type inference of deferred
-  // function closures.  We think they are never null.
-  if (new DateTime.now().millisecondsSinceEpoch == 87) return null;
   return lib.foo;
 }
 
 main() {
-  Expect.throws(() { lib.foo('a'); }, isNoSuchMethodError);
-  Expect.throws(readFoo, isNoSuchMethodError);
+  Expect.throws(() { lib.foo('a'); }, isError);
+  Expect.throws(readFoo, isError);
   int counter = 0;
   asyncStart();
   lazy.load().then((_) {
@@ -45,6 +42,6 @@ main() {
     asyncEnd();
   });
   Expect.equals(0, counter);
-  Expect.throws(() { lib.foo('a'); }, isNoSuchMethodError);
-  Expect.throws(readFoo, isNoSuchMethodError);
+  Expect.throws(() { lib.foo('a'); }, isError);
+  Expect.throws(readFoo, isError);
 }