ART: Add object-readbarrier-inl.h

Move some read-barrier code into a new header. This prunes the
include tree for the concurrent-copying collector. Clean up other
related includes.

Test: mmma art
Change-Id: I40ce4e74f2e5d4c692529ffb4df933230b6fd73e
diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index db6f8ee..a7be73a 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -20,6 +20,7 @@
 
 #include <sys/stat.h>
 
+#include "android-base/stringprintf.h"
 #include "android-base/strings.h"
 
 #include "base/logging.h"