[llvm] [GlobalMerge]Prefer use global-merge-max-offset instead of the target-specific constant offset. (PR #165591)

[David Green via llvm-commits]

davemgreen wrote:

> This is for opt tool, delete it will let opt -global-merge fail.

I see - perhaps something ew can remove when it moves to the NPM.

https://github.com/llvm/llvm-project/pull/165591