refactor: make test action expansion generic

Test configurations generated for LAVA should be platform independent,
LAVA expects job definitions to use the same format. There is no reason
for platform scripts to own any part of the job definition
expansion. Move the expansion code into generic scripts.

Change-Id: I821750947dcd5bd0040813c176bbf9220c0e75c0
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
3 files changed