Erlang/OTP 22 (and possibly earlier) provides :erts_debug.same/2, which will allow you to do the desired memory pointer test. However, note the function is undocumented and in a module named erts_debug, so you should only rely on it for debugging and testing, and never in production code.
In my almost 9 years using Erlang/Elixir, I have only used it once, which is to test that we are not needlessly allocating structs in Ecto. Here is the commit for reference.
PS: I have also added this same reply to the Stack Overflow thread above.
