[llvm] [VectorCombine] Avoid push_back in range-for (PR #196741)

[Hongyu Chen via llvm-commits]

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XChy wrote:

`ShuffleVectorInst *SV : make_range(Shuffles.begin(), Shuffles.end())` should be equivalent to `ShuffleVectorInst *SV : Shuffles`? Both compute the iterators before the loop, which will be invalidated by `push_back`.

https://github.com/llvm/llvm-project/pull/196741