Move mirror::ObjectArray to ObjPtr

Also reduce calls to ObjPtr::Ptr.

Bug: 31113334

Test: test-art-host -j32

Change-Id: I73e1b356972bb079b66332f00f7f07451601044e
diff --git a/runtime/mirror/array-inl.h b/runtime/mirror/array-inl.h
index 7cbcac8..d18781a 100644
--- a/runtime/mirror/array-inl.h
+++ b/runtime/mirror/array-inl.h
@@ -25,6 +25,7 @@
 #include "base/stringprintf.h"
 #include "class-inl.h"
 #include "gc/heap-inl.h"
+#include "obj_ptr-inl.h"
 #include "thread.h"
 
 namespace art {