[llvm] [BlockPlacement] Add flag to disable profile usage (PR #102956)

[Ellis Hoag via llvm-commits]

ellishg wrote:

Friendly ping for review @amharc.

This flag is also useful to triage size regressions when consuming profiles. Many other passes have similar flags. https://github.com/llvm/llvm-project/pull/102950 is a similar PR.

https://github.com/llvm/llvm-project/pull/102956