HTML Processor should respect `tag_name` argument in `next_tag()`

[dmsnell]

The HTML Processor currently ignores the tag_name provided if provided in its array form.

<?php
$processor->next_tag( array( 'tag_name' => 'DIV' ) );

It returns the next tag regardless of its name. It should instead continue scanning until it finds a tag of the given name or reaches the end of the document.

Trac ticket: Core-61581

Previously the HTML Processor was ignoring the tag_name argument in the next_tag() query if it existed. This was wrong adn would lead to calling code finding the very next tag, regardless of tag name, instead of the requested taag.

This patch adds the tag name detection code into next_tag() to fix the bug and ensure that next_tag() always returns only when finding a tag of the given name.

Follow-up to [56274].

[dmsnell]

In 58681:

HTML API: Respect tag_name query arg in HTML_Processor::next_tag()

Previously the HTML Processor was ignoring the tag_name argument in
the next_tag() query if it existed. This was wrong adn would lead to
calling code finding the very next tag, regardless of tag name, instead
of the requested taag.

This patch adds the tag name detection code into next_tag() to fix
the bug and ensure that next_tag() always returns only when finding
a tag of the given name.

Developed in ​https://github.com/WordPress/wordpress-develop/pull/6980
Discussed in https://core.trac.wordpress.org/ticket/61581

Follow-up to [56274].

Fixes #61581.

Merged in [58681]
​https://github.com/wordpress/wordpress-develop/commit/f90c8bf1ae620b7568851f6d6e155223a8a6bf73