Merge "Add the constant for IPv6 all-routers/nodes/hosts multicast address." am: 46baaac36b am: 71584aba6e

Original change: https://android-review.googlesource.com/c/platform/frameworks/libs/net/+/1562252

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I6942c6844c89048f785f2b6eaa4bb33a24fa6f93