[llvm] [DAG] visitEXTRACT_SUBVECTOR - accumulate SimplifyDemandedVectorElts demanded elts across all EXTRACT_SUBVECTOR uses (REAPPLIED) (PR #133401)

[Walter Lee via llvm-commits]

googlewalt wrote:

I applied this change and ran the internal tests that were timing out from #133083, and there were no issues, so LGTM from my side.


https://github.com/llvm/llvm-project/pull/133401