Simplify service wrapper initialization + make robust

- Simplify the logic, no more AtomicIntegers.
- Make robust -- if we know we've successfully created an instance before,
but the instance is now gone, re-initialize again.
- Added CTS.

Bug: 75964116
Fixes: 75964116
Bug: 71882178
Fixes: 71882178
Test: Manual test with UC Browser
Test: atest /android/pi-dev/cts/tests/tests/content/src/android/content/cts/ContextTest.java#testGetSystemService_multiThreaded
Change-Id: I12a9834d0f62e90e6f5d806a124cbdade415440c