[clang] [clang][Interp] Fix IntAP(s) to IntAP(s) casts (PR #69915)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

A bit more description about what the issue is and why this solves it would be helpful.

https://github.com/llvm/llvm-project/pull/69915