[llvm] [LLVM][AArch64]Add compare-and-branch assembly/disassembly instructions (PR #112726)

[Momchil Velikov via llvm-commits]

momchil-velikov wrote:

> Are additional disassembly tests in `llvm/test/MC/Disassembler/AArch64` required? (maybe they're in a later patch?)

Good point, I've totally forgotten about these tests!

But, no, dissembly is already tested, for example
```
// RUN: llvm-mc -triple=aarch64 -show-encoding -mattr=+cmpbr < %s \
// RUN:        | sed '/.text/d' | sed 's/.*encoding: //g' \
// RUN:        | llvm-mc -triple=aarch64 -mattr=+cmpbr -disassemble -show-encoding \
// RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-INST
```


https://github.com/llvm/llvm-project/pull/112726