url: fix inconsistent port in url.resolveObject

[imyller]

Checklist

• make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

url

Description of change

This commit fixes a bug where url.resolveObject returns conflicting host and port values.

$ node
> url.resolveObject('http://example.com:81', 'http://example.com:82');
Url {
  protocol: 'http:',
  slashes: true,
  auth: null,
  host: 'example.com:82',
  port: '81',
  hostname: 'example.com',
  hash: null,
  search: null,
  query: null,
  pathname: '/',
  path: '/',
  href: 'http://example.com:82/' }
> 

Fixes: #8213

[jasnell]

CI: https://ci.nodejs.org/job/node-test-pull-request/3792/
LGTM if CI is green.

[jasnell]

New CI: https://ci.nodejs.org/job/node-test-pull-request/3806/
Red in last run is most likely unrelated but just in case...

[jasnell]

Landed in 286d44e . Thank you!

[MylesBorins]

this does not land cleanly on v4.x @imyller would you be willing to manually backport against v4.x-staging

feel free to let me know if you have any questions