change: Rename data file test_hvd_basic.py to hvd_basic.py

With out this, one cannot run  non-horvod tests independently
with out installing horovod. command "python-k $test_names" is trying
to import "test_hvd_basic.py" file as its in data directory

Author: Naresh Kumar Kolloju

tests/data/horovod/test_hvd_basic.py renamed to tests/data/hvd_basic.py

@@ -41,7 +41,7 @@ def instance_type(request):
 @pytest.mark.canary_quick
 def test_horovod(sagemaker_session, instance_type, tmpdir):
     job_name = sagemaker.utils.unique_name_from_base('tf-horovod')
-    estimator = TensorFlow(entry_point=os.path.join(horovod_dir, 'test_hvd_basic.py'),
+    estimator = TensorFlow(entry_point=os.path.join(horovod_dir, 'hvd_basic.py'),
                            role='SageMakerRole',
                            train_instance_count=2,
                            train_instance_type=instance_type,
@@ -69,7 +69,7 @@ def test_horovod(sagemaker_session, instance_type, tmpdir):
 def test_horovod_local_mode(sagemaker_local_session, instances, processes, tmpdir):
     output_path = 'file://%s' % tmpdir
     job_name = sagemaker.utils.unique_name_from_base('tf-horovod')
-    estimator = TensorFlow(entry_point=os.path.join(horovod_dir, 'test_hvd_basic.py'),
+    estimator = TensorFlow(entry_point=os.path.join(horovod_dir, 'hvd_basic.py'),
                            role='SageMakerRole',
                            train_instance_count=2,
                            train_instance_type='local',