GenericBackend: Add _test_sense method

[mkoeppe]

This adds another test method, which all MIP backends pass.

CC: @dimpase

Component: numerical

Author: Matthias Koeppe

Branch/Commit: a3a9a0f

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/21499

[mkoeppe]

Branch: u/mkoeppe/add_test_sense_method

[mkoeppe]

Commit: a3a9a0f

[mkoeppe]

New commits:

a3a9a0f

GenericBackend._test_sense: New

[dimpase]

comment:3

We'll be away for 5 days, for a vacation...

[mkoeppe]

comment:4

Enjoy your vacation!
This is not urgent.

[mkoeppe]

comment:5

Still needs review...

[dimpase]

Reviewer: Dima Pasechnik

[dimpase]

comment:6

A lot of tests fail if I test with Nonexistent_LP_solver in --optional.
Should all these tests be tagged differently?
(another option would be to add a backend so named :-))

[vbraun]

Changed branch from u/mkoeppe/add_test_sense_method to a3a9a0f