… FakeTensorMode"

Stack from [ghstack](https://github.com/ezyang/ghstack) (oldest at bottom):

*  #151497
*  #151507
* __->__ #151495

## Introduction
`flex_attention`'s FakeTensor propagation `flex_attention_fake_impl` [permutes](https://github.com/pytorch/pytorch/blob/fb6ac2f16132f7953711ce6924bc2ee4a033228c/torch/_higher_order_ops/flex_attention.py#L459) the stride of `out` (the attention score) based on `query`'s stride. To enable `flex_attention` call on DTensor, this requires us add `as_strided` support on DTensor in `FakeTensorMode`. 

## Limited Support
Due to the complexity of supporting actual `as_strided` on DTensor, I choose to only enable a limited subset:
1. `as_strided` only works correctly in `FakeTensorMode` i.e. shape and strided propagation.
2. `as_strided` is only allowed in case where `size == input.shape` because this PR specifically unblocks the use case of `flex_attention_fake_impl`. 
3. `as_strided` requires `storage_offset=None` because the other case is not defined in DTensor.

## Test
`pytest test/distributed/tensor/test_view_ops.py -s -k test_as_strided`

cc H-Huang awgu wanchaol fegin fduwjj wz337 wconstab d4l3k tianyu-l

[ghstack-poisoned]