glsl: Delete bogus ir_set_program_inouts assert.

This assertion is bogus.  Varying structs, and arrays of structs, are
allowed by GLSL, and we can see them here.  While we currently don't
have any partial-variable support for those, simply returning false
and marking the entire thing as used is certainly legitimate.

I believe this is often swept under the rug by varying packing,
but that's disabled in certain tessellation situations.

Hit by 20 dEQP-GLES31.functional.tessellation.user_defined_io.* tests.

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>

src/compiler/glsl/ir_set_program_inouts.cpp

@@ -260,15 +260,19 @@ ir_set_program_inouts_visitor::try_mark_partial_variable(ir_variable *var,
     * lowering passes (do_vec_index_to_swizzle() gets rid of indexing into
     * vectors, and lower_packed_varyings() gets rid of structs that occur in
     * varyings).
+    *
+    * However, we don't use varying packing in all cases - tessellation
+    * shaders bypass it.  This means we'll see varying structs and arrays
+    * of structs here.  For now, we just give up so the caller marks the
+    * entire variable as used.
     */
    if (!(type->is_matrix() ||
         (type->is_array() &&
          (type->fields.array->is_numeric() ||
           type->fields.array->is_boolean())))) {
-      assert(!"Unexpected indexing in ir_set_program_inouts");
 
-      /* For safety in release builds, in case we ever encounter unexpected
-       * indexing, give up and let the caller mark the whole variable as used.
+      /* If we don't know how to handle this case, give up and let the
+       * caller mark the whole variable as used.
        */
       return false;
    }