Remove MethodReturn instruction

and pass
and fix all tests
move towards removing all vm instructions

lib/register/passes/return_implementation.rb

@@ -1,18 +0,0 @@
-module Register
-  class ReturnImplementation
-    def run block
-      block.codes.dup.each do |code|
-        next unless code.is_a? Virtual::MethodReturn
-        new_codes = []
-        # move the current message to new_message
-        new_codes << RegisterTransfer.new(code, Register.message_reg , Register.new_message_reg )
-        # and restore the message from saved value in new_message
-        new_codes << Register.get_slot(code,:new_message , :caller , :message )
-        #load the return address into pc, affecting return. (other cpus have commands for this, but not arm)
-        new_codes << FunctionReturn.new( code , Register.new_message_reg , Register.resolve_index(:message , :return_address) )
-        block.replace(code , new_codes )
-      end
-    end
-  end
-  Virtual.machine.add_pass "Register::ReturnImplementation"
-end

lib/register/register.rb

@@ -1,7 +1,6 @@
 require_relative "instruction"
 require_relative "register_value"
 require_relative "assembler"
-require_relative "passes/return_implementation"
 require_relative "passes/call_implementation"
 
 # So the memory model of the machine allows for indexed access into an "object" .