PCOUNT() returns zero for NULL_OBJECT argument

In the latest X# 3.0 compiler, following returns 0, instead of 1 as VO returns.
See also compiler test R848

```
FUNCTION Start( ) AS VOID
? TestMe(NULL_OBJECT) // zero in X# 3, one in X# 2 and in VO

FUNCTION TestMe (args) AS LONG CLIPPER        
    ? PCount()
RETURN PCount()
```