Check if freezer cgroup configuration is valid

Project Treble allows Android to upgrade to the latest version without
modifying vendor implementation. Some old vendor code might contain
outdated cgroup profiles, which override the correct ones in the system
partition. Improve isFreezerSupported() to detect those rare cases.

Bug: 277233783
Test: manually verify freezer with outdated cgroup configuration
Change-Id: Ife8c02a6d424965fce3e8ca158bf337dcb4faf1e