[llvm] [llvm-exegesis] Add AArch64 operand initializers, SetRegTo (PR #169912)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

Regarding test coverage, a couple thoughts:
1. It would be good if we at least assert something in a test, even if that is just the number of snippets successfully generated with a specific random seed so that there isn't back slide.
2. You don't gain much beyond a simple assertion. Asserting the machine code generated might not be a terrible idea, but I would expect the machine verifier to pick up most of the big issues.

https://github.com/llvm/llvm-project/pull/169912