tests: Adjust fbrtti.bi to define vptr as ANY PTR PTR

Now it's a bit closer to reality than before.
http://www.freebasic.net/forum/viewtopic.php?p=200337#p200337

It doesn't make a difference to tests using these macros though, since
they just compare the vptr value, and don't ever access it (not through
these macros anyways).