After the merge of !5288 (merged) the test
element_vkcolorconvert started to fail because it couldn't use ARGB format.
Digging on it I realized that I did a wrong code review (sorry!), because the semantics of mapping formats is the first column is for the non-sRGB formats and the second column for the sRGB transfer formats, in the case of RGB.
And now the old and venerable libs_vkformat unit test returned to its original checked values.
Also are other two (almost) cosmetic changes.