[scudo] Add memtag_test am: ecf52a746a am: 5fb7dc0868 am: ab89adbba1

Original change: https://android-review.googlesource.com/c/platform/external/scudo/+/1729753

Change-Id: If1f0bb15b76db9a90f46927ced9e1e332a4d0f74