Merge pull request #17112 from l-bat:ie_region

* Support nGraph Region

* Support region since OpenVINO 2020.2

* Skip myriad

modules/dnn/test/test_darknet_importer.cpp

@@ -530,6 +530,10 @@ TEST_P(Test_Darknet_layers, avgpool_softmax)
 
 TEST_P(Test_Darknet_layers, region)
 {
+#if defined(INF_ENGINE_RELEASE)
+     if (backend == DNN_BACKEND_INFERENCE_ENGINE_NGRAPH && INF_ENGINE_VER_MAJOR_GE(2020020000))
+        applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_NGRAPH, CV_TEST_TAG_DNN_SKIP_IE_VERSION);
+#endif
     testDarknetLayer("region");
 }