Refactor the EntitlementManager

1. Change ArraySet usage to BitSet
2. Change mCellularUpstreamPermitted to mLastCellularUpstreamPermitted.

Before this change:
a member variable(mCellularUpstreamPermitted) is
used to check whether cellular upstream is permitted, the code must
ensure to update this variable once entitlement result is changed or the
entitlement check is triggered but does not have a result yet.

In this change:
Instead of storing the information about whether cellular is permitted in
a member variable. The information is recalculated every time when user
call isCellularUpstreamPermitted(). Now isCellularUpstreamPermitted() is
always be used to check whether cellular upstream is permitted no matter
inside or outside EntitlementManager.
This make the code be easier to maintain that we do not need to care
when mCellularUpstreamPermitted need to be updated because the
information would be recalculated every time. And the recalculation is
lock free because this is only used inside tethering while running in
the same thread.

Bug: 141256482
Test: atest TetheringTests

Merged-In: Ic83f42ff4eec38adf039d55d80fcb9b0f16373cc
Change-Id: Ic83f42ff4eec38adf039d55d80fcb9b0f16373cc