Avoid EOVERFLOW problems with file-directory-p

Avoid EOVERFLOW problems with file-directory-p

This fixes a bug where (file-directory-p FOO) would fail if FOO
had an inode number out of range for ‘stat’.
* src/fileio.c (file_directory_p): Accept a Lisp string instead of
a C string.  All callers changed.  On non-MS-Windows hosts, use
openat with O_PATH|O_DIRECTORY if available, otherwise
file_accessible_directory_p unless it fails due to EACCESS,
otherwise stat.