Upgrade some tests to use annotations instead of 'clever' confuse() function

tests/language/generic_instanceof4_test.dart

Index: tests/language/generic_instanceof4_test.dart
diff --git a/tests/language/generic_instanceof4_test.dart b/tests/language/generic_instanceof4_test.dart
index 15896cb598551432d7733e177b4fbde3ecb3387b..95ff9bbb29567dcb22d47b54a295e7e5f1a2323a 100644
--- a/tests/language/generic_instanceof4_test.dart
+++ b/tests/language/generic_instanceof4_test.dart
@@ -6,9 +6,8 @@
 import "package:expect/expect.dart";
 
 class A<T> {
+  @NoInline()
   foo(x) {
-    // Don't inline.
-    if (new DateTime.now().millisecondsSinceEpoch == 42) return foo(x);
     return x is T;
   }
 }
@@ -16,9 +15,8 @@ class A<T> {
 class BB {}
 
 class B<T> implements BB {
+  @NoInline()
   foo() {
-    // Don't inline.
-    if (new DateTime.now().millisecondsSinceEpoch == 42) return foo();
     return new A<T>().foo(new B());
   }
 }