Try this:
$the_query = new WP_Query($args = array(
'post_type' => 'forms',
'tax_query' => array(
array(
'taxonomy' => 'form_category',
'field' => 'slug'
),
),
)
);
btw – Why do you have a 0 in this add_action? Remove it or change it to > 0.
add_action( 'init', 'my_taxonomies_product', 0 );