[clang] [CIR] Apply 'side-effect' attribute logic to the function as well. (PR #177242)

[Erich Keane via cfe-commits]

erichkeane wrote:

@andykaylor would love yoru approval or hint as to what you want me to do with the attribute/etc on this one.  

https://github.com/llvm/llvm-project/pull/177242