connection manager HTTP/2 tests crashes on OpenBSD

[TingDaoK]

Describe the bug

 The following tests FAILED:
	600 - connection_manager_single_http2_connection (SEGFAULT)
	602 - connection_manager_single_http2_connection_with_settings (SEGFAULT)
	604 - connection_manager_many_http2_connections (SEGFAULT)

The CI catches couple crash from openBSD, all related to connection manager with HTTP/2.

https://github.com/awslabs/aws-c-http/actions/runs/16332889023/job/46139186189?pr=524

We will need to look into this. #524

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

Don't segfault

Current Behavior

Segfault without trace back.

Reproduction Steps

#524 This branch adds the CI for those platform.

But we may need to get an openBSD somewhere to reproduce the issue.

Possible Solution

No response

Additional Information/Context

No response

aws-c-http version used

latest

Compiler and version used

gcc

Operating System and version

openbsd