Simplify fused location provider.

The previous location fusion algorithm produced very poor results
outdoors, where stale-but-accurate network locations had too much
influence over the final fused location.

I swapped the previous fusion algorithm out with an algorithm
that has been well-tested elsewhere and should produce superior
results.

Bug: 7341419
Change-Id: Iba71950a07907cbf26429c4e377b5e2ed91ba302