libprocessgroup: implement task profile validity checks

Provide profile validity check functions for cases when user wants to
check whether a profile can be successfully applied before actually
applying it. Add test cases to cover new APIs.

Also add a wrapper function for framework code to call it.

Bug: 277233783
Test: atest task_profiles_test
Test: manually verify freezer with outdated cgroup configuration
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Li Li <dualli@google.com>
Change-Id: Iefb321dead27adbe67721972f164efea213c06cb
Merged-In: Iefb321dead27adbe67721972f164efea213c06cb