Sessions committed later shouldn't cause earlier ones to fail
When 2 sessions have overlapping packages, the one committed earlier
should pass the overlapping check while the later one should fail.
1. Add a field to denote the time when a session is committed.
2. When doing overlapping check, only consider sessions that are
committed before the current session.
Bug: 174442862
Test: atest StagingManagerTest PackageInstallerSessionTest
Change-Id: Ieeafc879f32b1228d451307b194d65146c7496c1
5 files changed