gh-36255: numpy-1.25 compatibility
Fixes two doctest failures with numpy-1.25.x. One is a warning from
pythran that needs to be hidden (to avoid requiring a bleeding-edge
version of pythran), and the other is a buggy doctest that now triggers
a numpy warning.
URL: https://github.com/sagemath/sage/pull/36255
Reported by: Michael Orlitzky
Reviewer(s):
