Return a new C string initialized with txt

Property definitions

nitc $ NaiveInterpreter :: c_string_instance_from_ns
	# Return a new C string initialized with `txt`
	fun c_string_instance_from_ns(txt: CString, len: Int): Instance
	do
		var instance = c_string_instance_len(len)
		var val = instance.val
		txt.copy_to(val, len, 0, 0)

		return instance
	end
src/interpreter/naive_interpreter.nit:346,2--354,4