[C++] Valgrind fails consistently on Azure tests

[raulcd]

Describe the bug, including details regarding any error messages, version, and platform.

Our test-conda-cpp-valgrind job had been failing for a while to build due to an issue with xxhash. See:

• [CI][C++] test-conda-cpp-valgrind fails building vendored/xxhash.h #47475
• GH-47483: [C++] Bump vendored xxhash to 0.8.3 #47476

The above PR updates xxhash and fixes the build issue but the job still fails due to an azure test failing. The issue is unrelated to the previous one so we should fix it. Full log on the link

==17355== LEAK SUMMARY:
==17355==    definitely lost: 1,856 bytes in 8 blocks
==17355==    indirectly lost: 78,096 bytes in 40 blocks
==17355==      possibly lost: 0 bytes in 0 blocks
==17355==    still reachable: 9,874 bytes in 157 blocks
==17355==         suppressed: 0 bytes in 0 blocks
==17355== Reachable blocks (those to which a pointer was found) are not shown.
==17355== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==17355== 
==17355== For lists of detected and suppressed errors, rerun with: -s
==17355== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)

Component(s)

C++

[pitrou]

I've opened Azure/azure-sdk-for-cpp#6722 upstream. I'm not sure that is actually the issue, but still worth reporting.

[pitrou]

Ok, after some gdb-based investigation, it does seem like a bug in the Azure SDK.

[pitrou]

Issue resolved by pull request 47496
#47496