Renaming new start user tests

Renaming the start user tests to make clear that it was "started twice/once before in the past, and now we're timing the next start".

Bug: 266555909
Test: atest UserLifecycleTests#startUser_startedOnceBefore
Test: atest UserLifecycleTests#startUser_startedTwiceBefore
Test: atest UserLifecycleTests#startAndUnlockUser_startedTwiceBefore
Change-Id: Ib92e1c69027d05c1dbee7ce6b3620e6e6f8ccc7e