CI: Fixes Musca B1 platform tests

Also removes post build on NSOFF Musca platforms as that is not necessary, as
they would not be able to run on the hardware anyway without NS.

Change-Id: I458a6a0e3e0a8750cee590a059dc96663330a12b
Signed-off-by: Matthew Dalzell <matthew.dalzell@arm.com>
1 file changed