vrend: get rid of glShaderStorageBlockBinding

On GLES it is not supported, and on GL it seems to be irrelevant,
because the guest already handles this.

Update the test expectation accordingly.

Fixes #201

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Italo Nicola <italonicola@collabora.com>