[php-src] Issue #7887: isCloneable() on ReflectionEnum errors

Issue: https://github.com/php/php-src/issues/7887 Author: Crell ### Description The following code: ```php <?php enum A { case B; } $e = new ReflectionEnum(A::class); var_dump($e->isCloneable()); $c = new ReflectionClass(A::class); var_dump($c->isCloneable()); ``` Resulted in this output: ``` Fatal error: Uncaught Error: Cannot instantiate enum A in /in/IIhNF:8 Stack trace: #0 /in/IIhNF(8): ReflectionClass->isCloneable() #1 {main} thrown in /in/IIhNF on line 8 ``` But I expected this output instead: ``` false false ``` Right now, isCloneable() errors out on an Enum, regardless of whether it is called on ReflectionEnum or ReflectionClass. (The former is a child of the latter, so it's possible to reflect on an Enum with either Reflection class.) Since enums are not cloneable, I would expect it to simply return false in both cases. ### PHP Version 8.1.1 ### Operating System _No response_