Eliminate the need of ::testsing::ValuesIn() for CV_ENUM

Also cv::, cv::gpu:: and cv::ocl:: namespace prefixes can be safely omitted
inside CV_ENUM and CV_FLAGS

modules/gpu/test/test_threshold.cpp

@@ -46,8 +46,7 @@
 
 using namespace cvtest;
 
-CV_ENUM(ThreshOp, cv::THRESH_BINARY, cv::THRESH_BINARY_INV, cv::THRESH_TRUNC, cv::THRESH_TOZERO, cv::THRESH_TOZERO_INV)
-#define ALL_THRESH_OPS testing::Values(ThreshOp(cv::THRESH_BINARY), ThreshOp(cv::THRESH_BINARY_INV), ThreshOp(cv::THRESH_TRUNC), ThreshOp(cv::THRESH_TOZERO), ThreshOp(cv::THRESH_TOZERO_INV))
+CV_ENUM(ThreshOp, THRESH_BINARY, THRESH_BINARY_INV, THRESH_TRUNC, THRESH_TOZERO, THRESH_TOZERO_INV)
 
 PARAM_TEST_CASE(Threshold, cv::gpu::DeviceInfo, cv::Size, MatType, ThreshOp, UseRoi)
 {
@@ -88,7 +87,7 @@ INSTANTIATE_TEST_CASE_P(GPU_ImgProc, Threshold, testing::Combine(
     ALL_DEVICES,
     DIFFERENT_SIZES,
     testing::Values(MatType(CV_8UC1), MatType(CV_16SC1), MatType(CV_32FC1)),
-    ALL_THRESH_OPS,
+    ThreshOp::all(),
     WHOLE_SUBMAT));
 
 #endif // HAVE_CUDA