[clang] [analyzer] Speed up `CallDescriptionMap` lookups (PR #219441)

[Balázs Benics via cfe-commits]

steakhal wrote:

Hi there,
Before I'd look at the patch, let me ask a couple of clarifying questions.
1) Why did you work on this issue? I'd like to understand the motivation first.
2) Have you used some AI and to what degree?
3) Have you explored the llvm algorithms and datastructures that could help you with an implementation?

https://github.com/llvm/llvm-project/pull/219441