Fix leaking file descriptor for Ruby 3.4

The changes in net-ftp are a brute force way to find issues in the CI. They
might not work, and will probably be reverted.

library/net-ftp/mkdir_spec.rb

@@ -13,7 +13,7 @@
 
   after :each do
     @ftp.quit rescue nil
-    @ftp.close
+    @ftp.close rescue nil
     @server.stop
   end
 

library/net-ftp/mtime_spec.rb

@@ -13,7 +13,7 @@
 
   after :each do
     @ftp.quit rescue nil
-    @ftp.close
+    @ftp.close rescue nil
     @server.stop
   end
 

library/net-ftp/voidcmd_spec.rb

@@ -13,7 +13,7 @@
 
   after :each do
     @ftp.quit rescue nil
-    @ftp.close
+    @ftp.close rescue nil
     @server.stop
   end
 

library/socket/socket/connect_spec.rb

@@ -67,6 +67,8 @@
           client.connect(address)
         rescue Errno::ECONNREFUSED
           skip "Outgoing packets may be filtered"
+        ensure
+          client.close if client
         end
       }.should raise_error(IO::TimeoutError)
     end