turnip: Fix issues in tu_compute_pipeline_create() that may lead to crash

turnip: Fix issues in tu_compute_pipeline_create() that may lead to crash

The shader object is destroyed even if its creation failed. It is also
not destroyed if its compilation or upload fails, leading to leaks.

Finally, tu_compute_pipeline_create() should set output var
pPipeline to VK_NULL_HANDLE if it fails.

Avoids crash on
dEQP-VK.api.object_management.alloc_callback_fail_multiple.compute_pipeline

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3572>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3572>