st/glsl_to_tgsi: fix 64-bit integer bit shifts

st/glsl_to_tgsi: fix 64-bit integer bit shifts

Fix a bug that was caused by a type mismatch in the shift count between
GLSL and TGSI. I briefly considered adjusting the TGSI semantics, but
since both LLVM and AMD GCN require both arguments to be of the same type,
it makes more sense to keep TGSI as-is -- it reflects the underlying
implementation better.

I'm also sending out piglit tests that expose this error.

v2: use the right number of components for the temporary register

Reviewed-by: Marek Olšák <marek.olsak@amd.com>