Don't check "fake" closures (fix assertion)

Fixes oss-fuzz #53078

Author: dstogov

Zend/tests/first_class_callable_016.phpt

@@ -0,0 +1,16 @@
+--TEST--
+First class callables and &__call()
+--FILE--
+<?php
+class Foo {
+    public function &__call($method, $args) {
+        return $method;
+    }
+}
+
+$foo = new Foo;
+$bar = $foo->bar(...);
+echo $bar(),"\n";
+?>
+--EXPECT--
+bar

Zend/zend_vm_def.h

@@ -4166,7 +4166,7 @@ ZEND_VM_HOT_HANDLER(60, ZEND_DO_FCALL, ANY, ANY, SPEC(RETVAL,OBSERVER))
 		}
 
 #if ZEND_DEBUG
-		if (!EG(exception) && call->func) {
+		if (!EG(exception) && call->func && !(call->func->common.fn_flags & ZEND_ACC_FAKE_CLOSURE)) {
 			if (should_throw) {
 				zend_internal_call_arginfo_violation(call->func);
 			}