[llvm] CodeGen: Remove target hook for terminal rule (PR #165962)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> We are seeing a failure on a copy instruction of a non-general purpose register and I wonder how we can get around this optimization for specific register types/classes?

What do you mean by failure? Failures are just bugs and not a reason to maintain points of optimization configurability

https://github.com/llvm/llvm-project/pull/165962