Revert "fix #30462, update function_type tests to understand covariant generics"

tests/language_2/function_type/function_type56_test.dart

Index: tests/language_2/function_type/function_type56_test.dart
diff --git a/tests/language_2/function_type/function_type56_test.dart b/tests/language_2/function_type/function_type56_test.dart
index 521edede514d3bbafe8ac0739a4f9343b7c00088..f1af44e1d14f8b113724c93873cec24ea6a2f098 100644
--- a/tests/language_2/function_type/function_type56_test.dart
+++ b/tests/language_2/function_type/function_type56_test.dart
@@ -216,10 +216,10 @@ class U56<T> {
       });
     }
     if (tIsInt || tIsBool) {
-      Expect.equals(true, m1 is F1<int>);
-      Expect.equals(true, m1 is F1<bool>);
-      Expect.equals(true, confuse(m1) is F1<int>);
-      Expect.equals(true, confuse(m1) is F1<bool>);
+      Expect.equals(tIsInt, m1 is F1<int>);
+      Expect.equals(tIsBool, m1 is F1<bool>);
+      Expect.equals(tIsInt, confuse(m1) is F1<int>);
+      Expect.equals(tIsBool, confuse(m1) is F1<bool>);
     }
   }