Avoid closing directory we're iterating

Ruby 3.4 started error checking directory access and starts to raise
Errno::EBADF.

This particular loop iterates on all open file descriptors and one is
the directory listing from Dir.foreach.

In the past this could have led to leaked file descriptors, but it's
unlikely since it's likely the last opened file descriptor and have the
highest number.

Link: ruby/ruby@f2919bd
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2349352

Author: ekohl

lib/puppet/util.rb

@@ -478,8 +478,10 @@ def safe_posix_fork(stdin = $stdin, stdout = $stdout, stderr = $stderr, &block)
       $stderr = STDERR
 
       begin
-        Dir.foreach('/proc/self/fd') do |f|
-          if f != '.' && f != '..' && f.to_i >= 3
+        d = Dir.new('/proc/self/fd')
+        ignore_fds = ['.', '..', d.fileno.to_s]
+        d.each_child do |f|
+          if !ignore_fds.include?(f) && f.to_i >= 3
             begin
               IO.new(f.to_i).close
             rescue