Modify gated unit tests to fix Fairseq OSS (facebookresearch#2059)

Summary:
Pull Request resolved: facebookresearch#2059

test_ensemble_sequence_generator and test_export_ensemble_model are green on fbcode master but Pytorch 1.5 release cut happened before the TorchScript fix, so updating the gate to 1.6
Remove quantization test from fairseq as FBGEMMS is binded at OSS side. Will add the test back in fbtranslate but land this first to fix OSS side failures.

Reviewed By: myleott

Differential Revision: D21231873

fbshipit-source-id: 8a2ad7dbed118ca8e3f4c351c399a82fd9740445

tests/test_sequence_generator.py

@@ -118,7 +118,7 @@ def test_export_transformer(self):
         torch.jit.script(model)
 
     @unittest.skipIf(
-        torch.__version__ < "1.5.0", "Targeting OSS scriptability for the 1.5 release"
+        torch.__version__ < "1.6.0", "Targeting OSS scriptability for the 1.6 release"
     )
     def test_ensemble_sequence_generator(self):
         model = self.transformer_model
@@ -128,22 +128,11 @@ def test_ensemble_sequence_generator(self):
         scripted_model = torch.jit.script(generator)
         self._test_save_and_load(scripted_model)
 
-    @unittest.skipIf(
-        torch.__version__ < "1.5.0", "Targeting OSS scriptability for the 1.5 release"
-    )
-    def test_quantized_ensemble_sequence_generator(self):
-        model = torch.quantization.quantize_dynamic(
-            self.transformer_model, {torch.nn.Linear}, dtype=torch.qint8, inplace=True
-        )
-        generator = SequenceGenerator([model], self.task.tgt_dict, beam_size=2)
-        scripted_model = torch.jit.script(generator)
-        self._test_save_and_load(scripted_model)
-
 
 class TestJitEnsemble(TestJitSequenceGeneratorBase):
 
     @unittest.skipIf(
-        torch.__version__ < "1.5.0", "Targeting OSS scriptability for the 1.5 release"
+        torch.__version__ < "1.6.0", "Targeting OSS scriptability for the 1.6 release"
     )
     def test_export_ensemble_model(self):
         model = self.transformer_model