mesa/st: fix reference to nir->info after nir_to_tgsi
The nir shader memory is freed in nir_to_tgsi(), but the already freed shader info is referenced later when create compute state. To avoid referencing the freed memory, copy the shader info first before calling nir_to_tgsi.
Fixes vmx crash running aztec on SVGA driver. Fixes: 580f1ac4 ("nir: Extract shader_info->cs.shared_size out of union")
/cc @anholt