build-linux: copy smmute test app to platform output directory

Move a copy of smmute test application to the platform's output
directory so that it can be available for testing. Also cleanup
the respective tools path, where smmute test binary is copied,
during clean up.

Signed-off-by: Sathyam Panda <sathyam.panda@arm.com>
Signed-off-by: Vivek Gautam <vivek.gautam@arm.com>
Change-Id: Id49dcd4239f750979e83a05e3c37a52f69d13722