the callback function has 3 parameters and the 3rd is the tag name :
add_shortcode( 'all_faq', 'commonFunction' );
add_shortcode( 'wordpress_faq', 'commonFunction' );
function commonFunction($attr, $content, $tag) {
$cores = [
"all_faq" => "Faq",
"wordpress_faq" => "wp-Faq",
];
$args = array(
'post_type' => $cores[$tag],
'post_status' => 'publish',
'posts_per_page' => '-1'
);
// ...
}