[clang] [clang][dataflow] Discard unneeded `ExprToLoc` and `ExprToVal` entries. (PR #72850)

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martinboehme wrote:

> +1 for the simpler approach. I have a high-level question about the stability of the locations, its effect on convergence.

Answered in the inline comment.

> But I am happy with the `ExprToVal` part of the simple patch.

SG! Then let's continue the discussion on #72985?

https://github.com/llvm/llvm-project/pull/72850