add _doing_it_wrong to get_query_var and prevent fatal errors

[netweblogic]

The following scenario will throw a fatal error:

<?php
function parse_query_fail_test(){
        get_query_var('some_var_name', false);
}
add_action('parse_query', 'parse_query_fail_test');

function parse_query_fail_trigger(){
        get_posts();
}
add_action('plugins_loaded', 'parse_query_fail_trigger');

this could easily be avoided with a check and _doing_it_wrong function, similar to functions further down such as is_tax();

I would argue that the same could be done for get_queried_object(), get_queried_object_id() and set_query_var()

[netweblogic]

Suggested patch for get_query_var

[nileshdudakiya94]

has-patch has-unit-tests added

[ocean90]

@nileshdudakiya94 Your patch doesn't include a unit test, should it?

Related: #14729