Release DeviceState resources after test class is evaluated.

Since DeviceState is a ClassRule and thereby static, we explicitly release all expensive resources
it holds after the test class is executed.

Bug: 342407026

Test: atest CtsDevicePolicyTestCases

Change-Id: Ie4d8fb14e04f93b5522d0efb11375c72bd6e38b5
3 files changed