test(realm): perform LFA of RMM with Realm Payload

Add a test to execute the Realm payload with the existing RMM,
then perform LFA of RMM, and finally execute the Realm payload
again to ensure it runs with the newly activated RMM.

Change-Id: Ifbba462506c6b1c0c86aba1ac22a19cd414f54d9
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
4 files changed