[llvm] [memprof] Use std::vector<Frame> instead of llvm::SmallVector<Frame> (NFC) (PR #94432)

[David Blaikie via llvm-commits]

dwblaikie wrote:

My recollection was that even `SmallVector<T, 0>` had some advantages over std::vector ( https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h mentions some possible reasons for that) - so maybe worth using that instead?

https://github.com/llvm/llvm-project/pull/94432