build-sct.sh: update the UEFI SCT build script

The UEFI SCT test build script is updated to adapt to the latest build
procedure of UEFI SCT test suite. The corresponding changes to the
platform build configurations are included as well. For UFI SCT build,
the prerequisites package list is updated.

Signed-off-by: Zakaria Zahi <zakaria.zahi@arm.com>
Change-Id: Ib005c2c4cfe2964891b453eba37b3806ec41f83f