Generalised TensorMechanicsPlasticSimpleTester

This is already used in lots of tests so no further testing is needed

3 -> LIBMESH_DIM in FiniteStrainMultiPlasticity

Fixes #3951
Merge pull request #3953 from WilkAndy/simple_tester_3951

Generalised TensorMechanicsPlasticSimpleTester
Merge commit '52253f77fde3c105816f37fbd2faf1d0a8ddce05'