Windows build.

Author: trivialfis

tests/cpp/data/test_simple_dmatrix.cc

@@ -1,11 +1,12 @@
 // Copyright by Contributors
 #include <dmlc/filesystem.h>
 #include <xgboost/data.h>
-#include "../../../src/data/simple_dmatrix.h"
 
+#include <array>
+#include "xgboost/base.h"
+#include "../../../src/data/simple_dmatrix.h"
 #include "../../../src/data/adapter.h"
 #include "../helpers.h"
-#include "xgboost/base.h"
 
 using namespace xgboost;  // NOLINT