G-API: Parameterized render tests (#14892)
* Init commit
* Add mat size as test parameter
* Add test for text render
* Add test for rect render
* Add tests for line and circle
* Remove old render tests
* Init output mats
* Remove methods input arguments
* Add comment about data loss in BGR2NV12 conversion
* Add edge test cases
* Replace default color for out mats black -> white