[FUI21.1] Create NetworkIdentityUtils class am: 178bc96fdd am: 5995a9f441 am: bf31a1d9ac

Original change: https://android-review.googlesource.com/c/platform/frameworks/libs/net/+/1566233

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I184766de0cdaff19ef961aa4d37fb1dd15f0791e