Add test method UserLifecycleStressTest.switchToExistingGuestAndStartOverStressTest

This test method tests the following scenario consecutively 10 times:
1. Switch to existing guest
2. Mark it for deletion
3. Create and switch to a new guest
4. Remove previous guest
5. Switch to owner

Bug: 228022618
Test: atest com.android.server.pm.UserLifecycleStressTest
Change-Id: I38c3f57e8b008ca406813f0a5c82d9afa27aba6c