Remove duplication of target dependent types detection

[antoyo]

by moving them out of target-specific files like here and moving them in this function.

[winstonallo]

@rustbot claim

[rustbot]

Error: The feature assign is not enabled in this repository.
To enable it add its section in the triagebot.toml in the root of the repository.

Please file an issue on GitHub at triagebot if there's a problem with this bot, or reach out on #triagebot on Zulip.

[winstonallo]

Oops, I thought that Rustbot was available on this repo as well, my bad. I'd like to work on this, feel free to assign this issue to me if that's ok!

[antoyo]

Thanks for working on this!