[llvm] [BOLT] Adjust section sizes based on file offsets (PR #80226)

[Maksim Panchenko via llvm-commits]

maksfb wrote:

> > we should be using section offsets and not addresses to determine if section overlap
> 
> Why? What's the scenario where that makes a difference?

The answer is in the comment: "address continuity is not guaranteed as sections could be placed in different loadable segments."

Practically, it's needed for the Linux kernel. Let me see if I can produce a test case to simulate the section/segment layout.

https://github.com/llvm/llvm-project/pull/80226