Fix unkown length response

[TingDaoK]

Issue #, if available:

• aws-c-http does not read the entire response body after receiving Connection: Close #546

Description of changes:

• The HTTP client currently treat the response completes after the headers if no transfer encoding nor content-length received.
• But, the SPEC clearly mentioned that is a valid case for the response to provide indeterminate length response. (But request is not allowed to do so.)
• Add support to handle the case by leave the decoder

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.59259% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.78%. Comparing base (a9745ea) to head (fd61a12).

Files with missing lines	Patch %	Lines
source/h1_connection.c	75.00%	1 Missing ⚠️
source/h1_decoder.c	95.65%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #550      +/-   ##
==========================================
+ Coverage   79.72%   79.78%   +0.05%     
==========================================
  Files          28       28              
  Lines       11894    11920      +26     
==========================================
+ Hits         9483     9510      +27     
+ Misses       2411     2410       -1     

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[azkrishpy]

2xx (Successful) responses to a CONNECT request method (Section 4.3.6 of[RFC7231]) 
switch to tunnel mode instead of having a message body. All 1xx (Informational), 
204 (No Content), and 304 (Not Modified) responses do not include a message body.  
All other responses do include a message body, although the body might be of zero length.

we seem to ignore body for any value between 200 and 400? Is that correct?

[TingDaoK]

yeah, I was wrong about the math, this is supposed to be status code from 200-299.
Good catch!