Remove 'len' from lily_vm_execute.
Remove 'len' from lily_vm_execute.

i == len was impossible because o_return_val or o_vm_return is always at the
end of a method.

FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily,FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily,jesserayadkins/lily