Merge branch 'PHP-8.1' into PHP-8.2

* PHP-8.1:
Fix memory leak when calling xml_parse_into_struct() twice
Fix return type of stub of xml_parse_into_struct()

Fix return type of stub of xml_parse_into_struct()

Closes GH-12253.

Use true return type for XML functions which always return true

And fix xml_parser_set_option() which didn't return false on failure.

Closes GH-9539

Declare ext/xml constants in stubs (#9131)

Generate optimizer func info from stubs for various extensions (#7409)

ext/hash, ext/iconv, ext/mbstring, ext/xml, ext/zlib

Not serializable flag permeation

Implicitly enable function entry generation when class entry generation is enabled

Closes GH-6675

Add support for generating class entries from stubs

Closes GH-6289

Co-authored-by: Nikita Popov <nikita.ppv@gmail.com>

Rename XmlParser to XMLParser for consistency with XMLWriter/XMLReader

Fix XmlParser classname in stubs

Update ext/xml parameter names

Closes GH-6297.

Display string default values in stubs more uniformly

Settling on using quoted string

Promote warnings to exceptions in ext/gettext, ext/sysvmsg and ext/xml

Closes GH-5926

Add a bunch of missing argument types to stubs

Fix UNKNOWN default values in ext/xml

Generate function entries from stubs for a couple of extensions

Migrates ext/standard, ext/tidy, ext/tokenizer,
ext/xml, ext/xml_reader, and ext/xml_writer. Closes GH-5381.

Generate function entries for another batch of extensions

Closes GH-5352

Verify that all stubs have a return type

Add union return types with one class

Fix default value

Add ext/xml stubs