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

tests/language_2/function_type/function_type31_test.dart

Index: tests/language_2/function_type/function_type31_test.dart
diff --git a/tests/language_2/function_type/function_type31_test.dart b/tests/language_2/function_type/function_type31_test.dart
index 316fa9823a078be683170064e9c4cb4f3b1a4aac..781f71ef3fa9fb3a11769317cf89f912bd07a349 100644
--- a/tests/language_2/function_type/function_type31_test.dart
+++ b/tests/language_2/function_type/function_type31_test.dart
@@ -338,10 +338,10 @@ class U31<T> {
       });
     }
     if (tIsInt || tIsBool) {
-      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>);
+      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>);
     }
   }