[polly] [Polly] Use separate DT/LI/SE for outlined subfn. NFC. (PR #102460)

[Alexis Engelke via llvm-commits]

https://github.com/aengelke commented:

Looks good in general, but I don't really feel qualified to review Polly code.

https://github.com/llvm/llvm-project/pull/102460