Move mirror::ArtMethod to native

Optimizing + quick tests are passing, devices boot.

TODO: Test and fix bugs in mips64.

Saves 16 bytes per most ArtMethod, 7.5MB reduction in system PSS.
Some of the savings are from removal of virtual methods and direct
methods object arrays.

Bug: 19264997
Change-Id: I622469a0cfa0e7082a2119f3d6a9491eb61e3f3d
diff --git a/runtime/mirror/object.cc b/runtime/mirror/object.cc
index f9740bb..b177e2f 100644
--- a/runtime/mirror/object.cc
+++ b/runtime/mirror/object.cc
@@ -106,9 +106,8 @@
       : self_(self), orig_(orig), num_bytes_(num_bytes) {
   }
 
-  void operator()(Object* obj, size_t usable_size) const
+  void operator()(Object* obj, size_t usable_size ATTRIBUTE_UNUSED) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    UNUSED(usable_size);
     Object::CopyObject(self_, obj, orig_->Get(), num_bytes_);
   }