ART: Introduce predicated vector instructions.

This CL introduces a minimal changes to the IR to support
autovectorization with use of predicated execution of SIMD
instructions (e.g. Arm SVE).

Test: test-art-target, test-art-host.
Change-Id: Ibb7c5520fec6b858fb29f0dde19ec65501831a3a
10 files changed