Additional log instrumentation for multi-user

Log when app crash dialogs are shown:
Showing crash dialog for package <package.name> u<user_id>

Also log when BOOT_COMPLETED_DELIVERED to all receivers:
ActivityManager: Finished processing BOOT_COMPLETED for u<USER_ID>

Test: CreateUsersNoAppCrashesTest is passing. New messages are logged.
Bug: 37751789
Change-Id: Idef634007e9dd5f957eb6c5e97f40f3e6ac6dd18