Fixing test for osx

src/Solvers/petsc_solver_AMG_report.hpp

...sc_solver<double>_lid_driven_cavity_3d_p1_grid_0_test.vtk

...olver<double>_lid_driven_cavity_3d_p1_grid_0_test_osx.vtk

...sc_solver<double>_lid_driven_cavity_3d_p2_grid_0_test.vtk

...olver<double>_lid_driven_cavity_3d_p2_grid_0_test_osx.vtk

...sc_solver<double>_lid_driven_cavity_3d_p2_grid_1_test.vtk

...olver<double>_lid_driven_cavity_3d_p2_grid_1_test_osx.vtk

...sc_solver<double>_lid_driven_cavity_3d_p3_grid_0_test.vtk

...olver<double>_lid_driven_cavity_3d_p3_grid_0_test_osx.vtk

...sc_solver<double>_lid_driven_cavity_3d_p3_grid_1_test.vtk

...olver<double>_lid_driven_cavity_3d_p3_grid_1_test_osx.vtk

...sc_solver<double>_lid_driven_cavity_3d_p3_grid_2_test.vtk

...olver<double>_lid_driven_cavity_3d_p3_grid_2_test_osx.vtk