[Utils] Implement dump_on_oops feature

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
[Utils] implement random and rotateCursor

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
[Basic] Implement several tests

They test that:

 - throttling is working
 - yield semantic is working
 - cancel_dl_timer doesn't kill the system

Signed-off-by: Juri Lelli <juri.lelli@arm.com>