rtla/tests: Test setting default options

rtla/tests: Test setting default options

Add function to test engine to test with pre-set osnoise options, and
use it to test whether osnoise period (as an example) is set correctly.

The test works by pre-setting a high period of 10 minutes and stop on
threshold. Thus, it is easy to check whether rtla is properly resetting
the period to default: if it is, the test will complete on time, since
the first sample will overflow the threshold. If not, it will time out.

Cc: Luis Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20250320092500.101385-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Reviewed-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>