PathTools/t/cwd_enoent.t: a fixup to version check

v5.37.1-202-g0d6ab5e425 just added a version check for dragonfly;
however, it generates sprintf warnings unless the OS's version has
exactly two numeric components.

The fix is trivial.

dist/PathTools/t/cwd_enoent.t

@@ -28,7 +28,8 @@ foreach my $type (qw(regular perl)) {
 
         # https://github.com/Perl/perl5/issues/16525
         # https://bugs.dragonflybsd.org/issues/3250
-        my $osver = sprintf("%d%03d", ($Config{osvers} =~ /(\d+)/g));
+        my @vlist = ($Config{osvers} =~ /(\d+)/g);
+        my $osver = sprintf("%d%03d", map { defined ? $_ : '0' } @vlist[0,1]);
 	skip "getcwd() doesn't fail on non-existent directories on this platform", 4
 	    if $type eq 'regular' && $^O eq 'dragonfly' && $osver < 6002;