i965: Don't try to print the GLSL IR if it has been freed
Since commit 104c8fc2 the GLSL IR will be freed if NIR is being used. This was causing it to segfault if INTEL_DEBUG=wm is set. This patch just makes it avoid dumping the GLSL IR in that case. Reviewed-by:Ben Widawsky <ben@bwidawsk.net> Reviewed-by:
Tapani Pälli <tapani.palli@intel.com> (cherry picked from commit c0ca6c30)