Allow additional primitives for system classes

Don't show warnings for primitives that are defined in the VM but not the language.
Gives us a bit more freedom to reimplement the standard library at the VM level.

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Add primitives for <=, <>, >

Signed-off-by: Stefan Marr <git@stefan-marr.de>