Position of the method in virtual table

The relative position of this MMethod if perfect hashing is used, The absolute position of this MMethod if SST is used

Property definitions

nitc :: vm_optimizations $ CallSite :: offset=
	# Position of the method in virtual table
	#
	# The relative position of this MMethod if perfect hashing is used,
	# The absolute position of this MMethod if SST is used
	var offset: Int
src/vm/vm_optimizations.nit:159,2--163,16