for #30229.

The new static method CompWithSym._canonicalize_sym_antisym brings sym and antisym into a canonical form as sorted tuples of sorted tuples, with trivial symmetries and antisymmetries dropped.

Using it also removes some code duplication.

CC: @egourgoulhon

Component: linear algebra

Author: Matthias Koeppe

Branch/Commit: 66009e7

Reviewer: Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/34451