Fix compatibility issue for jdk 21

[k-sever]

JDK 21 introduced new method for ArrayList - removeLast:

/**
     * {@inheritDoc}
     *
     * @throws NoSuchElementException {@inheritDoc}
     * @since 21
     */
    public E removeLast() {
    ...

com.bazaarvoice.jolt.common.tree.WalkedPath has it's own implementation of removeLast that conflicts with the one from ArrayList in JDK 21.

This PR introduces a compatibility fix, so that it works for JDK 21 and older versions as well