test/openssl/test_ssl: fix flaky test case

Fix test_socket_open_with_local_address_port_context.

Often with MinGW, it seems EACCES is returned on bind when the port
number is unavailable. Ignore it just as we do for EADDRINUSE and
continue searching free port number.

Fixes: 98f8787 ("test/openssl/test_ssl: fix random failure in
SSLSocket.open test", 2020-02-17)

test/openssl/test_ssl.rb

@@ -99,7 +99,7 @@ def test_socket_open_with_local_address_port_context
         assert_equal ctx, ssl.context
         assert_equal random_port, ssl.io.local_address.ip_port
         ssl.puts "abc"; assert_equal "abc\n", ssl.gets
-      rescue Errno::EADDRINUSE
+      rescue Errno::EADDRINUSE, Errno::EACCES
       ensure
         ssl&.close
       end