GH-20783: support \f in trim, rtrim and ltrim

[LamentXU123]

I searched keyword trim in the codebase and fix every case I think related to the three functions. I didn't touch other features with trim implemented and missing \f. (such as trim in php filters or other code)
This PR changes:

• The default parameters characters of trim (also ltrim and rtrim) in the php interface, adding \f, source
• The behavior in php_trim_int (which effects php_trim), source
• Test case concerning trim, adding case of \f.

I am sending mails to internals now. After that I will write the NEWS file (and docs) if this feature is accepted.
doc of trim: https://www.php.net/manual/en/function.trim.php
This is my first time contributing to php so I am not so sure about this PR. Thanks.

ps: also a little detail. I change the default parameter to \f\n\t\r\v\0 using alphabetic orders. (abcdefghijklmn...)

[devnexen]

nit: personal opinion would be nice to share a helper for both cases e.g.

static zend_always_inline bool php_is_whitespace(char c)
{
    ...
}

but no need to bother now until the topic is discussed at least.