Test that unused vertex attributes don't get messed up with used ones in GL_ARB_vertex_program and fixed function shaders
The issue was found in Unreal Tournament 2004, see mesa#2758 (closed)
For fixed function I test that unused normal array doesn't affect color. It's a very narrow test.
For GL_ARB_vertex_program I test that tex coord attribute has a correct value if there are unused attributes between it and position. Or that generic attribute 7 has a correct value when 1 and 2 are unused.