Make test_s3_range_requests less flaky

[waahm7]

Description of changes:

• From one of the failed CI runs, I saw that

2024-04-03T21:25:53.2077062Z ***FAILURE*** Expected success at aws_http_headers_erase(range_get_headers, verify_header.name); got return value -1 with last error 0x0801

because of

2024-04-03T21:25:48.7011063Z [TRACE] [2024-04-03T21:23:05Z] [00007f7e703fe700] [http-stream] - id=0x6170005e0d00: Incoming header: Connection: close
2024-04-03T21:25:48.7014012Z [TRACE] [2024-04-03T21:23:05Z] [00007f7e703fe700] [http-stream] - id=0x6170005e0d00: Received 'Connection: close' header. This will be the final stream on this connection.

aws_http_headers_erase can fail if the header doesn't exist in the ranged_get_headers. Since this is in the ignored header list, we don't care if it exists in the ranged_get_response or not.

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

All modified and coverable lines are covered by tests ✅

Project coverage is 89.61%. Comparing base (3334843) to head (f399b00).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #423      +/-   ##
==========================================
- Coverage   89.63%   89.61%   -0.03%     
==========================================
  Files          20       20              
  Lines        5992     5988       -4     
==========================================
- Hits         5371     5366       -5     
- Misses        621      622       +1     

see 2 files with indirect coverage changes