ART: Fix GenSelect and GenFusedLongCmpBranch for ARM64

Depending on the result, we need to issue a wide csel. Also need
to handle constants, and src and dest being the same.

In GenFusedLongCmpBranch there is an ordering issue. If we swap
the inputs, we did not Load the second one.

Change-Id: Icb9876ca1288602d078b9fb89ea964ec2c910e0c