Test: Merge DejaGNU tests into single unified script

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Rootfs: Rewrite build script

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Rootfs: Proper handling of core and archs in target config

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Linux: Update build script

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Common: Extract get_tag function

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
DejaGNU: Use default as a testsuite source

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>