Made the crude ability less crude.

modules/ts/include/opencv2/ts/ts.hpp

@@ -578,6 +578,13 @@ int main(int argc, char **argv) \
     return RUN_ALL_TESTS(); \
 }
 
+// This usually only makes sense in perf tests with several implementations,
+// some of which are not available.
+#define CV_TEST_FAIL_NO_IMPL() do { \
+    ::testing::Test::RecordProperty("custom_status", "noimpl"); \
+    FAIL() << "No equivalent implementation."; \
+} while (0)
+
 #endif
 
 #include "ts_perf.hpp"