Remove sum performance test from matrix variable tests

Deleted the test_sum_performance function from test_matrix_variable.py. This test was benchmarking sum operations on matrix variables, but has been removed, possibly due to redundancy or irrelevance.

Author: Zeroto521

tests/test_matrix_variable.py

@@ -210,24 +210,6 @@ def test_matrix_sum_argument():
     assert (m.getVal(y) == np.full((2, 4), 3)).all().all()
 
 
-@pytest.mark.parametrize("n", [50])
-def test_sum_performance(n):
-    model = Model()
-    x = model.addMatrixVar((n, n))
-
-    # Original sum via `np.ndarray.sum`, `np.sum` will call subclass method
-    start_orig = time()
-    np.ndarray.sum(x)
-    end_orig = time()
-
-    # Optimized sum via `quicksum`
-    start_matrix = time()
-    x.sum()
-    end_matrix = time()
-
-    assert model.isGT(end_orig - start_orig, end_matrix - start_matrix)
-
-
 def test_add_cons_matrixVar():
     m = Model()
     matrix_variable = m.addMatrixVar(shape=(3, 3), vtype="B", name="A", obj=1)