Remove version check for ancient libxml version

[provokateurin]

Summary

New error with psalm 5.

With LIBXML_LOADED_VERSION I get Cannot perform a numeric operation with a non-numeric type '21004-GITv2.10.4'.
Looking at https://www.php.net/manual/en/libxml.constants.php it's not even documented...

EDIT: This version is so old that we can just remove this check.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[provokateurin]

Looking at the code I was able to make it even easier since the version was used to parse and format it, but there is already a variable for the formatted version.

[nickvergessen]

https://github.com/php/php-src/blob/master/ext/libxml/libxml.c#LL45C13-L45C34 hmm strange it's missing from the docs

[kesselb]

Good finding 👍

I think it should also work to remove the check for libxml 2.7.0.
It was released in 2008 (https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.7.4) so everyone should have it by now ;)

[provokateurin]

It was released in 2008

Haha ok then it's even easier :D