Implement array get and array put in optimizing.

Also fix a couple of assembler/disassembler issues.

Change-Id: I705c8572988c1a9c4df3172b304678529636d5f6
diff --git a/compiler/optimizing/code_generator_arm.h b/compiler/optimizing/code_generator_arm.h
index 85ab22b..610625c 100644
--- a/compiler/optimizing/code_generator_arm.h
+++ b/compiler/optimizing/code_generator_arm.h
@@ -175,12 +175,15 @@
     return InstructionSet::kThumb2;
   }
 
- private:
   // Helper method to move a 32bits value between two locations.
   void Move32(Location destination, Location source);
   // Helper method to move a 64bits value between two locations.
   void Move64(Location destination, Location source);
 
+  // Emit a write barrier.
+  void MarkGCCard(Register temp, Register card, Register object, Register value);
+
+ private:
   LocationsBuilderARM location_builder_;
   InstructionCodeGeneratorARM instruction_visitor_;
   ParallelMoveResolverARM move_resolver_;