functionPointerFor:inClass: has unused argument

[guillep]

functionPointerFor:inClass: has several implementations but the argument is not used.
We should refactor the code to remove the extra argument.

functionPointerFor: primIdx inClass: theClass
	"Find an actual function pointer for this primitiveIndex.  This is an
	opportunity to specialise the prim for the relevant class (format for
	example).  Default for now is simply the entry in the base primitiveTable."
	<api>
	<returnTypeC: 'void (*functionPointerForinClass(sqInt primIdx,sqInt theClass))(void)'>
	^primIdx > MaxPrimitiveIndex ifTrue: [0] ifFalse: [primitiveTable at: primIdx]