[llvm] [RISCV] Add TuneJumpIsExpensive (PR #191374)

[Sam Elliott via llvm-commits]

lenary wrote:

There was discussion about making this a subtarget feature (or not, as the decision was at that time) in https://github.com/llvm/llvm-project/pull/74647 - evidently that needs to be addressed, but we are a few years further on so I don't mind if the answers to the outstanding questions are different. 

https://github.com/llvm/llvm-project/pull/191374