Related to GH-6701

This deprecates passing null to non-nullable scale arguments of
internal functions, with the eventual goal of making the behavior
consistent with userland functions, where null is never accepted
for non-nullable arguments.

This change is expected to cause quite a lot of fallout. In most
cases, calling code should be adjusted to avoid passing null. In
some cases, PHP should be adjusted to make some function arguments
nullable. I have already fixed a number of functions before landing
this, but feel free to file a bug if you encounter a function that
doesn't accept null, but probably should. (The rule of thumb for
this to be applicable is that the function must have special behavior
for 0 or "", which is distinct from the natural behavior of the
parameter.)

RFC: https://wiki.php.net/rfc/deprecate_null_to_scalar_internal_arg

Closes GH-6475.

* PHP-8.0:
  Make finfo_open() $magic_database nullable

Empty string was interpreted as a special value here, which indicates
that the default magic database should be used. It makes more sense
to use null for this purpose.

The documentation also explicitly mentions that null can be used.

Closes GH-6675

Closes GH-6669

Besides our general desire to get rid of the legacy resource types,
this is particularly appealing for fileinfo, because there are already
respective objects.

Closes GH-5987.

* PHP-7.4:
  Fix #77961: finfo_open crafted magic parsing SIGABRT

libmagic may abort the running process, which is not desirable for PHP;
we raise a fatal error instead.

Closes GH-6437.

This has apparently been forgotten when updating to libmagic 5.39.