Instruction scheduling for ARM.

Performance improvements on various benchmarks with this CL:

benchmarks     improvements
---------------------------
algorithm                1%
benchmarksgame           2%
caffeinemark             2%
math                     3%
stanford                 4%

Tested on ARM Cortex-A53 CPU.

The code size impact is negligible.

Test: m test-art-host
Test: m test-art-target
Change-Id: I314c90c09ce27e3d224fc686ef73c7d94a6b5a2c