abitidy: Add method to calculate new ids for anonymous types am: 4ccad53441

Original change: https://android-review.googlesource.com/c/platform/external/libabigail/+/2197899

Change-Id: If74f786fa4f14f5dfbb9793731a27f0c397e3b45
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>