Fix #35272: cycles GPU crash with anisotropic shader in group node.

Problem was that due to group proxy node the anisotropic node did not detect
early enough that it needs generated texture coordinate data to generate the
tangent. Now the proxy nodes are removed earlier.

intern/cycles/render/shader.cpp

@@ -66,6 +66,12 @@ Shader::~Shader()
 
 void Shader::set_graph(ShaderGraph *graph_)
 {
+	/* do this here already so that we can detect if mesh or object attributes
+	 * are needed, since the node attribute callbacks check if their sockets
+	 * are connected but proxy nodes should not count */
+	if(graph_)
+		graph_->remove_unneeded_nodes();
+
 	/* assign graph */
 	delete graph;
 	delete graph_bump;