ext/standard: Fix setlocale() NUL byte truncation

[LamentXU123]

<?php
var_dump(setlocale(LC_ALL, "C\0invalid"));

string(1) "C"

See: https://3v4l.org/rHId2#v
New argument logic in try_setlocale_zval is inevitable because we need to know the argument position when we raise the ValueError (both the second and the third parameter of the setlocale function have the truncation issue)