[llvm] [BOLT] Add --pad-funcs-before=func:n (PR #117924)

[Peter Waller via llvm-commits]

peterwaller-arm wrote:

I am thinking that this is complementary to the seeded approach. In this case it's a surgical tool which can be used to deliberately modify a binary in a particular way with minimal incidental changes. I would also be interested in adding a seed-based approach at some point.

https://github.com/llvm/llvm-project/pull/117924