Add more RGBGFX tests #3041

Job	Run time
windows-mingw-build (32)	1m 2s
windows-mingw-build (64)	1m 39s
macos-static	2m 5s
windows (32, windows-2019)	4m 17s
unix (ubuntu-20.04, g++, make)	5m 22s
windows (32, windows-2022)	5m 43s
windows (64, windows-2019)	5m 1s
unix (ubuntu-20.04, g++, cmake)	5m 38s
windows (64, windows-2022)	5m 20s
unix (ubuntu-20.04, clang++, make)	5m 59s
unix (ubuntu-20.04, clang++, cmake)	5m 48s
unix (ubuntu-22.04, g++, make)	5m 43s
unix (ubuntu-22.04, g++, cmake)	5m 48s
unix (ubuntu-22.04, clang++, make)	3m 58s
unix (ubuntu-22.04, clang++, cmake)	4m 4s
unix (macos-14, clang++, make)	5m 42s
unix (macos-14, clang++, cmake)	6m 23s
windows-mingw-testing (windows-2019, 32)	2m 30s
windows-mingw-testing (windows-2019, 64)	4m 9s
windows-mingw-testing (windows-2022, 32)	2m 45s
windows-mingw-testing (windows-2022, 64)	4m 17s
	1h 33m 13s

Provide feedback