ts: refactor OpenCV tests

- removed tr1 usage (dropped in C++17)
- moved includes of vector/map/iostream/limits into ts.hpp
- require opencv_test + anonymous namespace (added compile check)
- fixed norm() usage (must be from cvtest::norm for checks) and other conflict functions
- added missing license headers

modules/dnn/test/test_torch_importer.cpp

@@ -44,7 +44,7 @@
 #include <opencv2/dnn/shape_utils.hpp>
 #include <opencv2/ts/ocl_test.hpp>
 
-namespace cvtest
+namespace opencv_test
 {
 
 using namespace std;