[13.x] Use native clamp function

[jnoordsij]

This replaces the manual Number::clamp implementation with the PHP native clamp, which is new in PHP 8.6 (unreleased). See also:

• https://wiki.php.net/rfc/clamp_v2
• [RFC] Add clamp function php/php-src#19434
• [8.6] Add clamp function symfony/polyfill#554

In doing so, it also introduces some tests for 'incorrect' behavior on providing reversed bounds, which currently leads to the incorrect and potentially unexpected outcome of always returning the 'max' value. By adding a deprecation now, this functionality can later be dropped to throw the ValueError and match the new default behavior.

[taylorotwell]

If it's working fine let's just leave it.

[jnoordsij]

I mainly did this again given it doesn't really work fine, as the min > max behavior is somewhat incorrect and deviates from what you might expect, hence moving towards a more universal solution would be preferable in my eyes.