Tests: use new instead of deprecated names.

test/boxmodels/1p/1ptestproblem.hh

test/boxmodels/2p/lensproblem.hh

test/boxmodels/2p2c/injectionproblem.hh

test/boxmodels/2p2cni/waterairproblem.hh

test/boxmodels/3p3c/infiltrationproblem.hh

test/boxmodels/3p3cni/columnxylolproblem.hh

test/boxmodels/3p3cni/kuevetteproblem.hh

test/boxmodels/co2/heterogeneousproblem.hh

test/boxmodels/co2ni/heterogeneousproblemni.hh

test/boxmodels/mpnc/forchheimer1pproblem.hh

test/boxmodels/mpnc/forchheimer2pproblem.hh

test/boxmodels/mpnc/obstacleproblem.hh

test/boxmodels/richards/richardslensproblem.hh

test/decoupled/1p/test_diffusionproblem.hh

tutorial/tutorialproblem_coupled.hh