http: read request even after response is closed

Trying to fix https://github.com/nodejs/node/issues/27916#issuecomment-511195010

I'm a little on deep water here and might need some guidance...

Checklist

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