[llvm] [AArch64] Reland merge index address with large offset into base address (PR #79951)

[via llvm-commits]

vfdff wrote:

Thanks @thurstond, I can reproduce with **llvm_build_ubsan/bin/llc** now. I check the build log and find missing **/usr/bin/time** , therefore, the build was not completed before
  > llvm_build_ubsan/bin/llc -verify-machineinstrs llvm-project/llvm/test/CodeGen/PowerPC/ppc64-nest.ll



https://github.com/llvm/llvm-project/pull/79951