array_uintersect should be varargs

[jwatzman]

Something is up in the way we handle array_uintersect with more than two arrays -- according to http://php.net/manual/en/function.array-uintersect.php I think it should be varargs, and we don't appear to be treating it that way, or something like that?

Repro: http://3v4l.org/RuBE1

Originally reported at http://stackoverflow.com/questions/31215963/invalid-operand-type-was-used-array-uintersect-expects-arrays

[jwatzman]

Fixed!