Fix ART build issues.

- Use ATTRIBUTE_UNUSED to avoid a warning about an unused
  argument in compiler/optimizing/nodes.h instead of
  simply commenting it out.
- Disable run test 002-sleep on ARM64.

Change-Id: I96911904289b73611e0fc168e7b597a9a2df8141
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index d7069ca..376e740 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -1776,7 +1776,7 @@
   Primitive::Type GetResultType() const { return GetType(); }
 
   bool CanBeMoved() const OVERRIDE { return true; }
-  bool InstructionDataEquals(HInstruction* /* other */) const OVERRIDE { return true; }
+  bool InstructionDataEquals(HInstruction* other ATTRIBUTE_UNUSED) const OVERRIDE { return true; }
 
   DECLARE_INSTRUCTION(TypeConversion);