skip fsdp2 low bit optim test in nightlies (#653)

* skip fsdp2 low bit optim test in nightlies

* Update test_low_bit_optim.py

* Update test_low_bit_optim.py

Author: msaroufim

test/prototype/test_low_bit_optim.py

@@ -230,6 +230,7 @@ def world_size(self) -> int:
         return 2
 
     @pytest.mark.skipif(not TORCH_VERSION_AFTER_2_4, reason="torch >= 2.4 required")
+    @pytest.mark.skipif(TORCH_VERSION_AFTER_2_5, reason="https://github.com/pytorch/ao/issues/652")
     @skip_if_lt_x_gpu(2)
     def test_fsdp2(self):
         optim_classes = [low_bit_optim.Adam8bit, low_bit_optim.Adam4bit]