[llvm] Reland "[llvm][AArch64] Copy all operands when expanding BLR_BTI bundle (#78267)" (PR #78719)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Oh, I see, that makes more sense.

Is there some reason we can't just change the definition of BLR_BTI so it takes the same operands as BLR?  Defining it to take different operands, then rewriting them to the form we want, seems like it's more complicated than necessary.

https://github.com/llvm/llvm-project/pull/78719