[clang] [CIR][AArch64] Lower NEON vsli/vsliq intrinsics (PR #198309)

[Andrzej Warzyński via cfe-commits]

banach-space wrote:

> Yes, I tried removing the bit-cast for these non-8-byte elements, but the tests failed — maybe I overlooked something. I'll revisit it this week and write a more detailed summary so it's easier for you to review.

Which test failed? I commented the bitcasts out myself and everything worked 🤔 It's possible that I am doing something wrong or missing something. Let's get to the bottom of this mystery!

https://github.com/llvm/llvm-project/pull/198309