ART: optimizing compiler: initial support for ARM64.

The ARM64 port uses VIXL for code generation, to which it defers work
like label binding and branch resolving, register type coherency
checking, and immediate values handling.

Change-Id: I0a44508c0c991f472a63e67b3469cdd878fe1a68
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Signed-off-by: Alexandre Rames <alexandre.rames@arm.com>
9 files changed