sage.rings.polynomial (and all of sage.rings) has lots of Cython modules that depend on various C/C++ libraries and will have to go into different distribution packages (#29705, #32501).

Thus we need to clear out __init__.py, which currently contains a workaround added in #25848 ("Some preparations for binding=True") in preparation for #22747/#26254. As this effort has stalled, we remove this workaround; a new solution can be found when #26254 gains traction again.

CC: @fchapoton @tscrim @kwankyu

Component: refactoring

Author: Matthias Koeppe

Branch/Commit: c41e11c

Reviewer: Marc Mezzarobba

Issue created by migration from https://trac.sagemath.org/ticket/32509