imgdiag: add memory page index for dirty entries am: 39d0caf5e5 am: bc76fa8c3a

Original change: https://android-review.googlesource.com/c/platform/art/+/2295219

Change-Id: I6fd90306b439ad11bf80dc7be20b2fb78adffcab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>