Improve equals and hashCode in CellIdentityXxx methods

The equals methods were a lot of dead code that boiled down to
seeing if two references pointed to the same object.  The hashCode
methods were likely to result in collisions on unequal objects.

Bug: 10328291
Change-Id: I4bd93efd1f4a34e9dec55ac05868df37368abd6a
4 files changed