Cssmin mucher slower on PHP with PCRE2 10.35 or +

[obriat]

Has seen on https://bugs.php.net/bug.php?id=81424

On line:

YUI-CSS-compressor-PHP-port/src/Minifier.php

Line 729 in 3cbf557

$css = preg_replace('/[^{};\/\n]+\{\}/S', '', $css);

The following regex /[^{};\/\n]+\{\}/S is not optimal with PCRE2 10.35+ (100 times slower) it should be rewrite.
The solution proposed on the PHP issue is not suitable here, a regexp expert should have a look at it