tests: remove redundant remote tests

With introduction of https://github.com/iterative/dvc-plugins,
all important tests are being ran there, so there is no need
for dvc repo to run them again.

This PR also removes some redundant/broken remote tests.

tests/func/test_checkout.py

@@ -752,9 +752,6 @@ def test_checkout_recursive(tmp_dir, dvc):
     }
 
 
-@pytest.mark.parametrize(
-    "workspace", [pytest.lazy_fixture("s3")], indirect=True
-)
 def test_checkout_for_external_outputs(tmp_dir, dvc, workspace):
     workspace.gen("foo", "foo")
 
@@ -844,9 +841,6 @@ def test_checkouts_for_pipeline_tracked_outs(tmp_dir, dvc, scm, run_copy):
     assert set(dvc.checkout()["added"]) == {"bar", "ipsum"}
 
 
-@pytest.mark.parametrize(
-    "workspace", [pytest.lazy_fixture("s3")], indirect=True
-)
 def test_checkout_external_modified_file(tmp_dir, dvc, scm, mocker, workspace):
     # regression: happened when file in external output changed and checkout
     # was attempted without force, dvc checks if it's present in its cache