Small refactor optim
blitz_exec_context gets only called if node->type == BLITZ_NODE_TYPE_CONTEXT (from blitz_exec_nodes), so checking for it is kind of useless.
Re-worked the code to ditch the check and make the function more readable

    if (node->type == BLITZ_NODE_TYPE_CONTEXT) {
        BLITZ_LOOP_MOVE_FORWARD(tpl);
        blitz_exec_context(tpl, node, parent_params, id, result, result_len, result_alloc_len TSRMLS_CC);
        BLITZ_LOOP_MOVE_BACK(tpl);
    }