* Otherwise they could GC in the middle of the test, and the files could
  then be deleted.

* There is no point to decode the bytes since we are closing the socket
  in Puma::MiniSSL::Socket#close.
* Also, calling #engine_read_all might cause further SSL errors, which
  could hide the first SSL error. This notably happens in
  TestPumaServerSSLClient#test_verify_fail_if_no_client_cert
  if the server is faster than the client. The error in that case is
  "System error: Success - 0 (Puma::MiniSSL::SSLError)" which is not
  actually an error, but there is also nothing to read further from SSL.

* 60 doesn't seem enough in CI for TestThreadPool#test_trim on TruffleRuby.

…ot exist

* This should speed up CI a bit for those jobs.