Allow class-level annotations to use @Rule instead of @ClassRule

This ensures individual recordings are made, rather than a single
recording of the entire suite. Also fixes a bug where an empty string
was being added to the list of active PIDs.

Bug: 285405318
Test: atest CtsPermission3TestCases
Change-Id: I14d2d2d352345949151046247f64ce6baf4e1ebe
1 file changed