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

[Craig Topper via llvm-commits]

topperc wrote:

> I did a quick evaluation and ran Coremark w/ and w/o `jump-is-expensive` and it shows a stable 1.65% performance gain on an 8-wide OoO RISC-V CPU.

I did a quick check on p550 and I think jump-is-expensive is worse by about 2%.

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