The answer to this question is very simple: Fully explain the situation to the teachers of BOTH classes and ask what is acceptable to them. Transparency is the key to avoiding almost all kinds of perceived inappropriate behaviour, and this is definitely such a case. The only right answer in your situation is what both teachers consider acceptable.
Believe it or not, standards of what is or is not plagiarism can sometimes be quite subjective, and in my experience, no area is more subjective than when it comes to questions about multiple submission and repurposing your own previous work (which some people call "self plagiarism", but I hate that term and so I avoid using it--I prefer to describe the behaviour rather than making the ridiculous suggestion that you can plagiarize yourself). What is acceptable to one teacher is unacceptable to another, and not only that, a teacher can change their mind on a situation simply because you take the time to openly explain what's going on.
Often, if you are transparent to both teachers about reusing material across classes, they will let you do it as long as you are very clear to them what is new and original in each submission. (At least, that was my experience in university when I used the same subject for an English paper and a Public Speaking speech, having fully informed both teachers of what I was doing.)