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

tests/language_2/function_type/function_type81_test.dart

Index: tests/language_2/function_type/function_type81_test.dart
diff --git a/tests/language_2/function_type/function_type81_test.dart b/tests/language_2/function_type/function_type81_test.dart
index c459d3800d7c110ca257d4020dfbb3c550c405ef..05c800781e5fee23608884bbe93a9201eb40aa95 100644
--- a/tests/language_2/function_type/function_type81_test.dart
+++ b/tests/language_2/function_type/function_type81_test.dart
@@ -267,10 +267,10 @@ class U81<T> {
       });
     }
     if (tIsInt || tIsBool) {
-      Expect.equals(tIsInt, m3 is F3<int>);
-      Expect.equals(tIsBool, m3 is F3<bool>);
-      Expect.equals(tIsInt, confuse(m3) is F3<int>);
-      Expect.equals(tIsBool, confuse(m3) is F3<bool>);
+      Expect.equals(true, m3 is F3<int>);
+      Expect.equals(true, m3 is F3<bool>);
+      Expect.equals(true, confuse(m3) is F3<int>);
+      Expect.equals(true, confuse(m3) is F3<bool>);
     }
   }