The hash is used to check whether the arginfo file needs to be
regenerated. PHP-Parser will only be downloaded if this is actually
necessary.
This ensures that release artifacts will never try to regenerate
stubs and thus fetch PHP-Parser, as long as you do not modify any
files.
Closes GH-5739.
Closes GH-5353. From now on, PHP will have reflection information
about default values of parameters of internal functions.
Co-authored-by: Nikita Popov <nikita.ppv@gmail.com>
