aemfvp-rme-a:boot.sh: Add 4 world boot validation script

Add changes in boot.sh to trigger multiple test runs.
One test run is FVP interative boot and the other is
FVP boot and validate the FVP logs to ensure 4 world
boot is successful.

Change-Id: I4243e38ffbf58bf96095d89f57fa838712a98113
Signed-off-by: Dilip Kota <dilip.kota@arm.com>