Optimize PySequence_Fast usage

Access arrays directly, avoiding type-check every time.

source/blender/python/intern/bpy_interface.c

@@ -742,9 +742,11 @@ int BPY_context_member_get(bContext *C, const char *member, bContextDataResult *
 		}
 		else {
 			int len = PySequence_Fast_GET_SIZE(seq_fast);
+			PyObject **seq_fast_items = PySequence_Fast_ITEMS(seq_fast);
 			int i;
+
 			for (i = 0; i < len; i++) {
-				PyObject *list_item = PySequence_Fast_GET_ITEM(seq_fast, i);
+				PyObject *list_item = seq_fast_items[i];
 
 				if (BPy_StructRNA_Check(list_item)) {
 #if 0