Modify PackageManagerPerfTest to work by itself agian

This change modifies PackageManagerPerfTest to work in isolation while
we work through an alternative per b/150624323

Test: atest PackageManagerPerfTest
Bug: 150624323
Change-Id: Iac1e040d4463e0e9609d1a7a6d88c9431bef2926
1 file changed