MAINT/ENH: add test for comparing classic ode and default ode_mlp structures

[nghi-truyen]

Add test for comparing classic ode and default ode_mlp structures once implicit Euler method is implemented (i.e., after #316).

def test_forward_run_mlp():
    ncpu = min(5, max(1, os.cpu_count() - 1))

    # % Test some multi layer perceptron models versus classical models
    # % TODO: add ode and ode_mlp once implicit Euler for neural ode is implemented
    mlp_to_cls_structure = {
        "zero-gr4_mlp-lr": "zero-gr4-lr",
        "zero-gr5_mlp-lr": "zero-gr5-lr",
        "zero-gr6_mlp-lr": "zero-gr6-lr",
        "zero-grd_mlp-lr": "zero-grd-lr",
        "zero-grc_mlp-lr": "zero-grc-lr",
        "zero-loieau_mlp-lr": "zero-loieau-lr",
    }