[clang] [LifetimeSafety] Add missing origins stats for lifetime analysis (PR #166568)

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DEBADRIBASAK wrote:

> I am not sure qualifiers are actually important in the stats. We could just use the const Type* as the key.

[Xazax-hun](https://github.com/Xazax-hun): Even if we do that, it will store a dangling pointer in the missing origin stats map.

https://github.com/llvm/llvm-project/pull/166568