Add test cases for method_exists with mixed and object types

Demonstrates that the false positive only occurs with template types
(object&T), not with plain mixed or object. For mixed,
ObjectWithoutClassType::isSuperTypeOf(MixedType) returns Maybe (mixed
is not necessarily an object), preventing the false positive. For plain
object, ObjectWithoutClassType::hasMethod() returns Maybe (via
ObjectTypeTrait), also preventing it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Comparison/data/bug-8217.php

@@ -9,10 +9,24 @@ class HelloWorld
 	 *
 	 * @param T $object
 	 */
-	public static function check($object): void
+	public static function checkTemplate($object): void
 	{
 		if (is_object($object) && method_exists($object, 'method')) {
 			echo 1;
 		}
 	}
+
+	public static function checkMixed(mixed $value): void
+	{
+		if (method_exists($value, 'method')) {
+			echo 1;
+		}
+	}
+
+	public static function checkObject(object $object): void
+	{
+		if (method_exists($object, 'method')) {
+			echo 1;
+		}
+	}
 }