tests: Check that count of vertex atomic counters enough for test
In OpenGL 4.6 (Table 23.57: Implementation Dependent Vertex Shader Limits)
specification said, that minimum value of MAX_VERTEX_ATOMIC_COUNTERS is 0.
Therefore if we use them we have to check available count.
Signed-off-by: Illia Iorin illia.iorin@globallogic.com