Currently the prefetch code returns WT_ERROR if __wt_ref_addr_copy return false:

    WT_ENTER_GENERATION(session, WT_GEN_SPLIT);
    if (__wt_ref_addr_copy(session, pe->ref, &addr)) {
        WT_ERR(__wt_page_in(session, pe->ref, WT_READ_PREFETCH));
        WT_ERR(__wt_page_release(session, pe->ref, 0));
    } else
        ret = (WT_ERROR);

Instead of returning an error, we may as well skip that entry.

Motivation:
Currently, if the server gets an error code other than 0, it exits, see WT-13155. As part of allowing specific error codes, we also found out that this error was not necessarily needed to be returned.