[llvm] [ADT] ImutAVLFactory: avoid overhead of vector for freelist (PR #196534)

[Christoph Cullmann via llvm-commits]

christoph-cullmann wrote:

Tried to improve the commit subject to better fit other commits in that area, I hope I didn't make it worse.

Thanks already that you did take a look at this.

https://github.com/llvm/llvm-project/pull/196534