Move casts.h and stl_util.h into base/.

Change-Id: Idb3bfa5cec3d146e488031d91265737cde2b4cf4
diff --git a/src/oat_file.cc b/src/oat_file.cc
index d3e1079..b201630 100644
--- a/src/oat_file.cc
+++ b/src/oat_file.cc
@@ -16,9 +16,9 @@
 
 #include "oat_file.h"
 
+#include "base/stl_util.h"
 #include "base/unix_file/fd_file.h"
 #include "os.h"
-#include "stl_util.h"
 
 namespace art {