Non-functional: Encapsulate testing for IO that is supposed to be arrayed...

Non-functional:  Encapsulate testing for IO that is supposed to be arrayed with extra level for per-vertex data.

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@27169 e7fa87d3-cd2b-0410-9028-fcbf551c1848