[llvm] [BOLT][Instrumentation] Initial instrumentation support for RISCV64 (PR #133882)

[via llvm-commits]

WangJee wrote:

> As we’ve previously discussed, there may be overlap in our work on this feature. To avoid duplication of effort, I think we should disscuss about how to collaborate with each other. @WangJee

Sure,  I was trying to use llvm-bolt to optimize MySQL, there are still some bugs，such as #135711. I have made temporary fixes locally. Maybe we can work together to solve these problems. 

https://github.com/llvm/llvm-project/pull/133882