gallivm/nir: fix shuffleup tests.

gallivm/nir: fix shuffleup tests.

So the shuffleup tests did a shuffle up with const 5,
we'd use invocation id (0..8) shuffle it down by 5,
get (-5..3), then call llvmshufflevector with that
which is totally illegal.

There might be a nicer way to fix this, but I can't see
it straight away, just bail on the fast path.

Fixes:
dEQP-VK.subgroups.shuffle.compute.subgroupshuffleup*

Cc: mesa-stable
Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23484>