[llvm] [RISCV] Implement RISCVInstrInfo::isAddImmediate (PR #72356)

[Alex Bradbury via llvm-commits]

asb wrote:

> > This appears to be breaking sanitizers: https://lab.llvm.org/buildbot/#/builders/168/builds/16852 https://lab.llvm.org/buildbot/#/builders/5/builds/38376
> 
> Since it's late for Alex, I'm working on a patch.

Thanks for that Craig, really appreciate it.

https://github.com/llvm/llvm-project/pull/72356