Do type checks in ArraySet without read barriers.

Do type checks in ArraySet without read barriers.

This approach is valid in the case of Baker and non-Baker
read barriers.

Benchmarks (ARM64) score variations on Nexus 5X with CPU
cores clamped at 960000 Hz (aosp_bullhead-userdebug build,
medians of 10 runs for each suite):
- Ritzperf - average (lower is better):       -0.44% (virtually unchanged)
- CaffeineMark - average (higher is better):  -0.20% (virtually unchanged)
- DeltaBlue (lower is better):                -4.08% (slightly better)
- Richards - average (lower is better):       -0.57% (virtually unchanged)
- SciMark2 - average (higher is better):      -0.52% (virtually unchanged)

Details about Ritzperf benchmarks with meaningful variations
(lower is better):
- GenericCalcActions.MemAllocTest:            +3.02% (slightly worse)

Details about Richards benchmarks with meaningful variations
(lower is better):
- gibbons                                     -5.01% (better)

Boot image code size variation on Nexus 5X
(aosp_bullhead-userdebug build):
- total ARM64 framework Oat files size change:
  83127840 bytes -> 83082656 bytes (-45184 bytes, -0.05%)
- total ARM framework Oat files size change:
  72571872 bytes -> 72522796 bytes (-49076 bytes, -0.07%)

Test: ART_USE_READ_BARRIER=true ART_HEAP_POISONING=true m test-art-host
Test: ART_USE_READ_BARRIER=true ART_HEAP_POISONING=true m test-art-target
Bug: 29516974
Bug: 12687968
Change-Id: I8fe130156ace87dd2e4a15d9f8b4111287e735b3