TRACE shouldn't default to chunked encoding

[HQidea]

• Version: all
• Platform: all
• Subsystem: none

example:

// server.js
const http = require('http');

const server = http.createServer((req, res) => {
  res.setHeader('x-req-headers', JSON.stringify(req.headers));
  res.end();
});
server.on('clientError', (err, socket) => {
  socket.end('HTTP/1.1 400 Bad Request\r\n\r\n');
});
server.listen(8000);

// client
const http = require('http');

const options = {
  hostname: 'localhost',
  port: 8000,
  path: '/any',
  method: 'trace'
};

// Make a request
const req = http.request(options);
req.end();

req.on('response', (res) => {
  console.log(res.headers);
});

// result
'x-req-headers': '{"host":"localhost:8000","connection":"close","content-length":"0"}'

As you can see, I haven't added a content-length header, but node itself adds it for me.

According to rfc7231:

A client MUST NOT send a message body in a TRACE request.

and rfc7230:

A user agent SHOULD NOT send a
Content-Length header field when the request message does not contain
a payload body and the method semantics do not anticipate such a
body.

After doing some digging, I recommend changing the value of useChunkedEncodingByDefault for TRACE.

https://github.com/nodejs/node/blob/master/lib/_http_client.js#L165-L173

and here are two references:
aef0960
#2703