Mark flaky test as xfail on 3.5.0

Ref: #5795

Author: nicoddemus

testing/test_collection.py

@@ -860,6 +860,11 @@ def test_exit_on_collection_with_maxfail_smaller_than_n_errors(testdir):
     assert "test_03" not in res.stdout.str()
 
 
+@pytest.mark.xfail(
+    condition=sys.version_info[:3] == (3, 5, 0),
+    strict=False,
+    reason="flaky on py 3.5.0 #5795",
+)
 def test_exit_on_collection_with_maxfail_bigger_than_n_errors(testdir):
     """
     Verify the test run aborts due to collection errors even if maxfail count of