Fix language_2/f_bounded_quantification4_test

This isn't quite what the test was doing before, but the test was completely broken before so /shrug.

Change-Id: Idc3b6e1eab3b0c444f7100f01eecc5f27991df9a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/115900
Auto-Submit: Mayank Patke <fishythefish@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Commit-Queue: Mayank Patke <fishythefish@google.com>

tests/language_2/f_bounded_quantification4_test.dart

@@ -8,8 +8,10 @@ import "package:expect/expect.dart";
 
 class A<T extends B<T>> {}
 
-class B<T> extends A {}
+class B<T extends B<T>> extends A<T> {}
+
+class Foo<T extends B<T>> extends B<Foo<T>> {}
 
 main() {
-  Expect.equals("B<B<dynamic>>", new B<B>().runtimeType.toString());
+  Expect.equals("Foo<Foo<B<dynamic>>>", new Foo<Foo>().runtimeType.toString());
 }