[llvm] [CodeGen] Increase NumVisited limit in TwoAddressInstructionPass to 18 (PR #80627)

[Nikita Popov via llvm-commits]

nikic wrote:

> ⚠️ We detected that you are using a GitHub private e-mail address to contribute to the repo. Please turn off [Keep my email addresses private](https://github.com/settings/emails) setting in your account.

Please resolve this warning.

https://github.com/llvm/llvm-project/pull/80627