Redirect loop occurs in taxonomy archive with URL-encoded slug.

[Toro_Unit]

The following steps will occur.

1. Create taxonomy with rewrite => false.

<?php
        $args = array(
                'label'            => 'Genre',
                'public'           => true,
                'rewrite'           => false,
        );

        register_taxonomy( 'genre', array( 'post' ), $args );

2. Create a term with URL-encoded slugs. ( example: 🏠, ワードプレス )
3. Set Permalink structure to to something other than Plain.
4. Go to the archive of the created term.
5. Redirect loop.

remove_action( 'template_redirect', 'redirect_canonical' ), it will not occur.

The issue is $redirect['query'] and $original['query'] are never equal because it's comparing the urlencoded vs non urlencoded version.

For example

$original['query'] = 'genre=%e3%83%af%e3%83%bc%e3%83%89%e3%83%97%e3%83%ac%e3%82%b9'
$redirect['query'] = 'genre=ワードプレス'

Basically the _value_ of _genre_ are the same, urlencoded-wise.

We still use the same logic as the previous $compare_original !== $compare_redirect, we just changed it so that we can handle the query difference.

This still needs more eyes and testing.

Trac ticket: https://core.trac.wordpress.org/ticket/52376

[donmhico]

The PR above is a potential fix for this issue. It still needs more testing.