[llvm] [SandboxIR] Implement Instruction flags (PR #103343)

[via llvm-commits]

vporpo wrote:

> actually, I think the Instruction version of some of these methods are not widely used, only the FPMathOperator versions. we might be able to do some cleanup and remove these from Instruction

So how should we proceed? Shall I stash this until we do the cleanup?

https://github.com/llvm/llvm-project/pull/103343