Make core/internal.hpp a private header

modules/ts/src/gpu_perf.cpp

@@ -40,11 +40,10 @@
 //
 //M*/
 
+#include "precomp.hpp"
 #include "opencv2/ts/gpu_perf.hpp"
 #include "opencv2/core/gpumat.hpp"
 
-#include "cvconfig.h"
-
 #ifdef HAVE_CUDA
     #include <cuda_runtime.h>
 #endif

modules/ts/src/precomp.hpp

@@ -3,6 +3,7 @@
 #include "opencv2/core/core_c.h"
 #include "opencv2/core/utility.hpp"
 
+#include "opencv2/core/private.hpp"
 
 #ifdef GTEST_LINKED_AS_SHARED_LIBRARY
 #error ts module should not have GTEST_LINKED_AS_SHARED_LIBRARY defined