[llvm] [memprof] Use a lambda instead of std::bind (NFC) (PR #144940)

[Snehasish Kumar via llvm-commits]

snehasish wrote:

> But I did not consider that you have to pass the object you are calling on into the call. Sorry for the noise.

TIL about std::mem_fn from your comment, thanks!

https://github.com/llvm/llvm-project/pull/144940