fp8 grouped mm compile issue

[danielvegamyhre]

Error

AttributeError: 'FakeTensor' object has no attribute '__tensor_flatten__'

Repro

• CUDA_VISIBLE_DEVICES=7 pytest test/prototype/moe_training/test_training.py -v -s

[danielvegamyhre]

fyi @brucechanglongxu @lizamd

skipping the test for now in #4045 (which fixes a different padding related issue) but since you folks are working on fp8 rowwise it would be great if you are able to take a look at this as part of that!