nir/builder: Add a name format arg to nir_builder_init_simple_shader().

This cleans up a bunch of gross sprintfs and keeps the caller from needing
to remember to ralloc_strdup.  I added a couple of '"%s", name ? name :
""' to radv where I didn't fully trace through whether a non-null name was
being passed in.

I also took the liberty of adding a basic name to a few shaders (pan_blit,
unit tests)

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7323>

src/intel/blorp/blorp_nir_builder.h

@@ -29,10 +29,8 @@ blorp_nir_init_shader(nir_builder *b,
                       gl_shader_stage stage,
                       const char *name)
 {
-   *b = nir_builder_init_simple_shader(stage, NULL);
+   *b = nir_builder_init_simple_shader(stage, NULL, "%s", name ? name : "");
    ralloc_adopt(mem_ctx, b->shader);
-   if (name != NULL)
-      b->shader->info.name = ralloc_strdup(b->shader, name);
    if (stage == MESA_SHADER_FRAGMENT)
       b->shader->info.fs.origin_upper_left = true;
 }