Wp_deregister_script() doesn’t work

Paste it into your themes functions.php
As you have said that you are working on a child theme, then paste this code into your child themes functions.php

add_action( 'wp_print_scripts', 'deq_der_script', 100 );

function deq_der_script() {
    wp_dequeue_script( 'quovolver' );
    wp_deregister_script( 'quovolver' );
}