Adds past event possibilities to the tribe_events shortcode

past_events.php

<?php function tribe_past_events_shortcode( $atts ) {
    if ( ! class_exists( 'Tribe__Events__Pro__Shortcodes__Tribe_Events' ) ) return '';
    add_action( 'parse_query', 'tribe_past_events_shortcode_modify_query' );
    $shortcode = new Tribe__Events__Pro__Shortcodes__Tribe_Events( $atts );
    return $shortcode->output();
}

function tribe_past_events_shortcode_modify_query( $query ) {
    $query->set( 'tribe_is_past', true );
    remove_action( 'parse_query', 'tribe_past_events_shortcode_modify_query' );
}

add_shortcode( 'tribe_past_events', 'tribe_past_events_shortcode' );

folks could do [tribe_past_events view="list"]
obviously, we'd be trusting them not to perform madness like [tribe_past_events view="month"]
probably has shortcomings but may also be a reasonable start point (in advance of full-on support being rolled into [tribe_events] itself)