https keepalive and chunking disabled problem

[esmq2092]

when original server return chunk encoding but ats disabled chunking at all...
ats(7.0.0) have to close the client connection when transaction had done...(all i mention here are cache miss requests)，

there's no problem for http requests, but i observed strange behavior for https request when use different version of wget as user-agent...

---

1. Wget/1.12 + http1.0 + keepalive, it works fine...
   GET /? HTTP/1.0
   User-Agent: Wget/1.12 (linux-gnu)
   Accept: /
   Host: a.b.com
   Connection: Keep-Alive

---

2. when switch to Wget/1.16 + http1.1 + keepalive, error occurs....
   GET /? HTTP/1.1
   User-Agent: Wget/1.16 (linux-gnu)
   Accept: /
   Host: a.b.com
   Connection: Keep-Alive

it will cause infinite loop generating error message like this : Read error at byte 39814 (The TLS connection was non-properly terminated.).Retrying.

and i known this message is actually emit by gnutls, both gnutls 3.0.22 and 3.3.8 have the problem....

3. when switch to Wget/1.16 + http1.1 and without keepalive, the problem gone....

when turn on chunking can fix the problem,
still i want to known that is the problem about ats or gnutls ?

[esmq2092]

when follow conditions are met, the gnutls will emit error message

1. original server return chunking data
2. ats configure to disable chunking at all
3. http1.1 client and use Keep-Alive connection
4. client build with gnutls
5. https request

[bryancall]

Linked with #1651

[bryancall]

We should verify the configuration options are working correctly for the 9.0.0 release.

[bryancall]

The configuration option in question is proxy.config.http.chunking_enabled (https://docs.trafficserver.apache.org/en/latest/admin-guide/files/records.config.en.html?highlight=chunking#proxy.config.http.chunking_enabled)