[llvm] [SystemZ][z/OS] Move emission of PPA1 (PR #208543)

[Ulrich Weigand via llvm-commits]

https://github.com/uweigand commented:

>There is an interesting restriction during emission: emitting debug information closes the text section. As result, emitting the delayed PPA1 data does not work in the current place together with emitting debug information.

Can you add a test case verifying that this is now fixed with the PR?

A few other comments inline.

https://github.com/llvm/llvm-project/pull/208543