mx cleanup [1/x]: unbreak mx_formats tests

Summary:

There tests are:
1. not all passing locally, due to excessive recompiles
2. mostly not running in CI (case by case)

This PR fixes (1).  A future PR will improve on (2).

Test Plan:

```
pytest test/prototype/mx_formats/ -s -x
```

Reviewers:

Subscribers:

Tasks:

Tags:

ghstack-source-id: e21b656e09297f12239be4255832c59672236dc3
ghstack-comment-id: 2593881934
Pull Request resolved: #1569

Author: vkuzo

test/prototype/mx_formats/test_mx_linear.py

@@ -26,6 +26,16 @@
     pytest.skip("Unsupported PyTorch version", allow_module_level=True)
 
 
+# source: https://stackoverflow.com/a/22638709
+@pytest.fixture(autouse=True)
+def run_around_tests():
+    # 1. before test - set up (currently do nothing)
+    # 2. run test
+    yield
+    # 3. after test - teardown
+    torch._dynamo.reset()
+
+
 @pytest.mark.skipif(not torch.cuda.is_available(), reason="CUDA not available")
 @pytest.mark.parametrize("elem_dtype", SUPPORTED_ELEM_DTYPES)
 @pytest.mark.parametrize("bias", [True, False])