[llvm] [AArch64][Vectorizer] Enable scalable factor-3 interleaving (PR #217370)

[Harry Ramsey via llvm-commits]

Harry-Ramsey wrote:

> It was about correctness I was interested, not the performance exactly (although that is important too). Do you see problems? Like in MultiSource/Benchmarks/BitBench/uuencode/uuencode.c?

Ah in this case, I see no reported failures in my `results.json`, all tests `PASS`.

https://github.com/llvm/llvm-project/pull/217370