Merge pull request opencv#17842 from anton-potapov:gapi_debug_log

Author: alalek

modules/gapi/src/logger.hpp

@@ -13,9 +13,11 @@
 #  include "opencv2/core/utils/logger.hpp"
 #  define GAPI_LOG_INFO(tag, ...)    CV_LOG_INFO(tag, __VA_ARGS__)
 #  define GAPI_LOG_WARNING(tag, ...) CV_LOG_WARNING(tag, __VA_ARGS__)
+#  define GAPI_LOG_DEBUG(tag, ...)    CV_LOG_DEBUG(tag, __VA_ARGS__)
 #else
 #  define GAPI_LOG_INFO(tag, ...)
 #  define GAPI_LOG_WARNING(tag, ...)
+#  define GAPI_LOG_DEBUG(tag, ...)
 #endif //  !defined(GAPI_STANDALONE)