[llvm] [FunctionAttrs] deduce attr `cold` on functions if all CG paths call a `cold` function (PR #101298)

[via llvm-commits]

goldsteinn wrote:

> @goldsteinn your change seems to be causing a test failure on a bot https://lab.llvm.org/buildbot/#/builders/174/builds/3661, can you take a look and revert if you need time to investigate?

Looking into it. I think I just need to update the tests. If its more complicated I will revert.

https://github.com/llvm/llvm-project/pull/101298