This changes the lpsolver test to explicitly test the available
linear solvers we have - either CoinMP, LpSolver or both. This
prevents that a newly added solver will be automatically tested
as it can have a different behaviour for the tested input values.
Reviewed-on: https://gerrit.libreoffice.org/34813Tested-by: Jenkins <email@example.com>
Reviewed-by: Tomaž Vajngerl <firstname.lastname@example.org>