Revert^2 "[AppOps] Remove unwanted UidState objects more quickly"

Changes made since initial submission:
  Fix fatal error mUidStates.remove(i)->mUidStates.removeAt(i)
  Reverse iteration order over pkgOps since items are removed
  Rename iteration variables to be discriptive

Reason for revert: change will be amended to fix initial issue

Bug: 320850079
Bug: 325556565
Test: Reboot in single and multi user cases

Change-Id: I9b1d50c4ebd416217140e1662f6bfc878b670642