Re-land "fix #30462, update function_type tests to understand covariant generics"

tests/language_2/function_type/function_type19_test.dart

Index: tests/language_2/function_type/function_type19_test.dart
diff --git a/tests/language_2/function_type/function_type19_test.dart b/tests/language_2/function_type/function_type19_test.dart
index 5fbf47abe069e29392e7eb9cb06cbcf32bfa595e..d2e9c6a12a03152ef3982a2994fda8a9b92be81d 100644
--- a/tests/language_2/function_type/function_type19_test.dart
+++ b/tests/language_2/function_type/function_type19_test.dart
@@ -282,10 +282,10 @@ class U19<T> {
       });
     }
     if (tIsInt || tIsBool) {
-      Expect.equals(tIsInt, m2 is F2<int>);
-      Expect.equals(tIsBool, m2 is F2<bool>);
-      Expect.equals(tIsInt, confuse(m2) is F2<int>);
-      Expect.equals(tIsBool, confuse(m2) is F2<bool>);
+      Expect.equals(true, m2 is F2<int>);
+      Expect.equals(true, m2 is F2<bool>);
+      Expect.equals(true, confuse(m2) is F2<int>);
+      Expect.equals(true, confuse(m2) is F2<bool>);
     }
   }