Remove object_utils.h.

Break into object_lock, field_helper and method_helper.
Clean up header files following this.
Also tidy some of the Handle code in response to compiler errors when resolving
the changes in this CL.

Change-Id: I73e63015a0f02a754d0866bfaf58208aebcaa295
diff --git a/runtime/reflection.cc b/runtime/reflection.cc
index 41421bc..0af4117 100644
--- a/runtime/reflection.cc
+++ b/runtime/reflection.cc
@@ -20,14 +20,14 @@
 #include "common_throws.h"
 #include "dex_file-inl.h"
 #include "jni_internal.h"
+#include "method_helper.h"
 #include "mirror/art_field-inl.h"
 #include "mirror/art_method-inl.h"
-#include "mirror/class.h"
 #include "mirror/class-inl.h"
-#include "mirror/object_array.h"
+#include "mirror/class.h"
 #include "mirror/object_array-inl.h"
+#include "mirror/object_array.h"
 #include "nth_caller_visitor.h"
-#include "object_utils.h"
 #include "scoped_thread_state_change.h"
 #include "stack.h"
 #include "well_known_classes.h"