Skip uncommitted depth/stencil test validation

Skip uncommitted depth/stencil test validation

The test in UncommittedDepthStencil expects the stencil buffer to be
unmodified because the shader is doing an uncommitted sparse fetch

This is incorrect, the depth/stencil should be unmodified only if
the depth/stencil buffer are uncommitted and it's not the case,
they are fully-committed non-sparse depth/stencil buffer

This change skip uncommitted depth/stencil test validation

Affects:

KHR-GL45.sparse_texture2_tests.*

Components: OpenGL

VK-GL-CTS issue: 439

Change-Id: I909937081f7058d0fbc57469626ab3d34d43486a