abitidy: Add method to calculate new ids for anonymous types am: 4ccad53441 am: 1aed691eab am: 20e910e059 am: 75668a20e7

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

Change-Id: Iaf22957786f013d91b5660533cf8af89bf1698b4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>