Commit pending state after mutiple uid updates

If the proc state switches from fg to bg, then the uid state commit is
delayed, but if switched back to fg before the uid state had updated
then we need to fix the issue where the bg state update is still
committed.

Also use MIN_PRIORITY_UID_STATE instead of UID_STATE_CACHED in case the
min state changes.

Fixes: 247111208
Bug: 248207394
Test: Locally run the broken tests
      Add new unit test in following commit
Change-Id: I8a8a6477071f6f916152dc107c0b9fcf4dc1c7bf