[llvm] [BOLT][WIP] Always treat function entry as code (PR #160161)

[Maksim Panchenko via llvm-commits]

maksfb wrote:

@yavtuk do you have an example where we have data at the start of the function? I'd like to consider us treating such cases differently, i.e. shift the function entry point to an actual code location.

https://github.com/llvm/llvm-project/pull/160161