Fix ReflectionClass stub

[VincentLanglet]

While trying dev-master branch, I got a new error @orklah
https://psalm.dev/r/364700858b

Those stubs were introduced in #8722 (cc @Ocramius)
and this is the only mistake I found.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/364700858b

<?php

$reflection = new \ReflectionClass((string) rand(0, 1));
$property = $reflection->getProperty('types');

Psalm output (using commit 8223332):

ERROR: TooManyArguments - 4:26 - Too many arguments for ReflectionClass::getProperty - expecting 0 but saw 1

INFO: UnusedVariable - 4:1 - $property is never referenced or the value is not used

[orklah]

Thanks!