Consolidate HotSpot and JDK tests for CgroupSubsystemFactory

There's a large amount of duplication between these two test cases:

https://github.com/openjdk/jdk/blob/02fec1e6e5b6728c13763718c98cf5db68b1cce3/test/hotspot/jtreg/containers/cgroup/CgroupSubsystemFactory.java
https://github.com/openjdk/jdk/blob/02fec1e6e5b6728c13763718c98cf5db68b1cce3/test/jdk/jdk/internal/platform/cgroup/TestCgroupSubsystemFactory.java

The two test cases should be consolidated.