Vanilla GLPK 4.65 frequently prints a warning message "Long-step dual simplex will be used". Sage patches its GLPK to skip this, and some distros use a patched GLPK as well, but not all of them. For the systems where there is only an unpatched GLPK, we should ignore this warning message in doctesting.

CC: @mkoeppe

Component: packages: standard

Author: John Palmieri

Branch: f38dbdb

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/29317