Skip flash_attn_split test

tests/test_flash_attn.py

@@ -625,6 +625,7 @@ def test_flash_attn_unpadded(seqlen, d, dropout_p, causal, dtype):
         # assert torch.allclose(dv, dv_ref, rtol=rtol, atol=atol)
 
 
+@pytest.mark.skipif(True, reason='Experimental, not being used')
 @pytest.mark.parametrize('dtype', ([torch.float16] if is_sm75 else [torch.float16, torch.bfloat16]))
 # @pytest.mark.parametrize('dtype', [torch.float16])
 @pytest.mark.parametrize('causal', [False, True])