fix order of multiplication in coxeter_groups #34799
Description
The method pi.binary_factorizations silently returned wrong results for elements in Permutations(n), because the order of multiplication was wrong.
I also add some tests.
CC: @tscrim
Component: categories
Author: Martin Rubey
Branch/Commit: 37d60d4
Reviewer: Travis Scrimshaw
Issue created by migration from https://trac.sagemath.org/ticket/34799