Fix memory leak of ctx_pool.contexts

[neverpanic]

Description

Related: https://bugzilla.redhat.com/show_bug.cgi?id=2327985

Checklist

• Code modified for feature bug
• Test suite updated with functionality tests
• Test suite updated with negative tests
• Documentation updated

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• This feature/change has adequate documentation added
• Code conform to coding style that today cannot yet be enforced via the check style test
• Commits have short titles and sensible commit messages
• Coverity Scan has run if needed (code PR) and no new defects were found

[Jakuje]

Wondering why we did not catch it with the address sanitizer CI.

[beldmit]

@Jakuje I think it's msan, not asan

[Jakuje]

@Jakuje I think it's msan, not asan

I think the asan has lsan module which should detect memory leaks too:

https://clang.llvm.org/docs/LeakSanitizer.html

But it looks like it needs ASAN_OPTIONS=detect_leaks=1, which is not present here. Let me add it in separate PR.

The msan on the other hand requires rebuilds of the whole module including dependencies to avoid false positives if I remember well.

[neverpanic]

Are the CI failures expected or a side effect of the free?

[simo5]

I broke kryoptic CI, I know how to fix it, we do not need to block on it.