[llvm] [AArch64] Reduce the cost of repeated sub-shuffle (PR #139331)

[Qinkun Bao via llvm-commits]

qinkunbao wrote:

Hi, could you take a look at the buildbot failure?

https://lab.llvm.org/buildbot/#/builders/94/builds/7184

https://github.com/llvm/llvm-project/pull/139331