ARM: VIXL32: Do a code cleanup.

This commit is mostly about changing the VIXL-based code generator
to use the new helper functions in more places.

Test: ART_USE_VIXL_ARM_BACKEND=true m test-art-host
Test: ART_USE_VIXL_ARM_BACKEND=true m test-art-target
Change-Id: Ibe35f6a133d5822cc3b7a876cc54590cdaca67fb
3 files changed