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 :white_check_mark:

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

Additional details and impacted files

[](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/423?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs) ```diff @@ 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](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/423/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs)