[llvm] [Inline] Accumulate the cost of the inlined function to the new call site (PR #111104)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

I believe part of the design of the new inliner was that it should be idempotent. As in rerunning the inliner should not result in any changes. If you accumulate inline costs between function calls, that breaks idempotency. I'd want more justification besides a vague "the inliner inlined too much stuff in one case" to break that.

https://github.com/llvm/llvm-project/pull/111104