arm64: Fix VarHandle intrinsics for non-Baker read barrier.

It turns out the artReadBarrierSlow() ignores the passed
reference and reloads the field from the object. This makes
some of the VarHandle intrinsics broken for the TABLELOOKUP
configuration. This change disables the broken variants of
these intrinsics (but leaves support code in place) and
cleans up locations for those variants that remain active.

Also refactor reference argument checks and do a few other
small cleanups (renames, comment updates, etc.).

Test: testrunner.py --target --64 --optimizing
Test: Repeat with ART_USE_READ_BARRIER=false ART_HEAP_POISONING=true.
Test: Repeat with ART_READ_BARRIER_TYPE=TABLELOOKUP.
      (Ignore two pre-existing checker test failures.)
Bug: 71781600
Change-Id: I8d28a4883771a8db2b283737bb643b36c7038c26
3 files changed