message: Fix empty files upload test
  Fix emulation of blank file field upload
  Replace cURL file uploader with raw socket
  Resolve Cannot upload empty file or blank file field
diff: --TEST--
  swoole_http_server: upload files empty
  --SKIPIF--
  -<?php
  -require __DIR__ . '/../include/skipif.inc';
  -skip_if_function_not_exist('curl_init');
  -skip_if_function_not_exist('curl_file_create');
  -?>
  +<?php require __DIR__ . '/../include/skipif.inc'; ?>
  --FILE--
  <?php
  require __DIR__ . '/../include/bootstrap.php';
  @@ -13,21 +9,37 @@ require __DIR__ . '/../include/bootstrap.php';
  $pm = new ProcessManager;
  $pm->parentFunc = function () use ($pm) {
  - $formData = [
  - 'file1' => curl_file_create('/dev/null', 'text/plain', 'empty.txt'),
  - 'file2' => curl_file_create('/dev/null', 'application/octet-stream', ''),
  - ];
  + $boundary = "------------------------d3f990cdce762596";
  + $body = implode("\r\n", [
  + "--$boundary",
  + 'Content-Disposition: form-data; name="file1"; filename="empty.txt"',
  + 'Content-Type: text/plain',
  + '',
  + '',
  + "--$boundary",
  + 'Content-Disposition: form-data; name="file2"; filename=""',
  + 'Content-Type: application/octet-stream',
  + '',
  + '',
  + "--$boundary--",
  + '',
  + ]);
  + $request = implode("\r\n", [
  + 'POST / HTTP/1.1',
  + "Content-Type: multipart/form-data; boundary=$boundary",
  + 'Content-Length: ' . strlen($body),
  + '',
  + '',
  + $body,
  + ]);
  - $ch = curl_init();
  - curl_setopt($ch, CURLOPT_URL, "http://127.0.0.1:{$pm->getFreePort()}");
  - curl_setopt($ch, CURLOPT_HEADER, 0);
  - curl_setopt($ch, CURLOPT_POST, 1);
  - curl_setopt($ch, CURLOPT_HTTPHEADER, ['Expect:']);
  - curl_setopt($ch, CURLOPT_POSTFIELDS, $formData);
  - curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  - $result = curl_exec($ch);
  - curl_close($ch);
  + $sock = stream_socket_client("tcp://127.0.0.1:{$pm->getFreePort()}");
  + fwrite($sock, $request);
  + stream_set_chunk_size($sock, 2 * 1024 * 1024);
  + $response = fread($sock, 2 * 1024 * 1024);
  + fclose($sock);
  + $result = ltrim(strstr($response, "\r\n\r\n"));
  echo "$result\n";
  $pm->kill();
  };
  