UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
1. 
generate cert by `openssl req -x509 -newkey rsa:2048 -nodes -sha256 -subj '/CN=localhost' \
  -keyout localhost-privkey.pem -out localhost-cert.pem`

nodejs 9.11.1 with server.js code here
```
const http2 = require('http2');
const fs = require('fs');

const server = http2.createSecureServer({
  key: fs.readFileSync('localhost-privkey.pem'),
  cert: fs.readFileSync('localhost-cert.pem')
});
server.on('error', (err) => console.error(err));
server.on('socketError', (err) => console.error(err));

server.on('stream', (stream, headers) => {
  // stream is a Duplex
  if (headers[':path'] === '/') {
    stream.respond({
      'content-type': 'text/html',
      ':status': 200
    });
    stream.pushStream({ ':path': '/test.js' }, (err, pushStream) => {
      pushStream.on('error', console.error)
      pushStream.respond({
        ':status': 200,
        'content-type': 'application/javascript' 
      });
      pushStream.end('alert("push success")');  
    });
    stream.end('<h1>Hello World</h1><script src="/test.js"></script>');
  }
});

server.listen(8443);
```
start up by `node server.js`
2. view https://locahost:8443 in chrome. ignore no secure infos
3. no 'push success' alerted

What is the expected behavior?
alert 'push success'

What went wrong?
it seems push refused by chrome via no secure https cert.

I tested in safari and firefox both of them worked.

Did this work before? N/A 

Chrome version: 65.0.3325.181  Channel: stable
OS Version: OS X 10.12.6
Flash Version: