[Test] multicast forwarding from LLA/MLA address test

Added E2E test cases to verify that packets from Thread network with
link-local/mesh-local source address to multicast group with scope
larger than realm-local are not forwarded to infra link.

Bug: 325770316

Test: atest ThreadNetworkIntegrationTests:android.net.thread.BorderRoutingTest
Change-Id: I77cb8dbc43d0a2d6936a2a4db45e9dea541ea3c0
2 files changed