##</code><code>##

use strict;
use warnings;
use XML::Twig;

my $twig = XML::Twig->new(
    twig_handlers => { tr => \&prune_tr },
    pretty_print  => 'indented',
);

$twig->parse( \*DATA );
$twig->print;

sub prune_tr {
    my ($handler, $tr) = @_;
    $tr->delete unless $tr->children;
}

__DATA__
<table>
    <tr>
        <td>ZZZ</td>
        <td>YYY</td>
        <td>XXX</td>
    </tr>

    <tr>
    </tr>

    <tr>
        <td>FFF</td>
        <td>SSS</td>
        <td>GGG</td>
    </tr>

    <tr>
    </tr>

    <tr>
        <td>WWW</td>
        <td>EEE</td>
        <td>TTT</td>
    </tr>
</table>