Fix static shape propagation in aten.as_strided

[raayandhar]

Intermediate view operations were not properly propagating static shapes. Thanks to Zach for pointing out how to fix this issue, see #4325 for more discussion. They key change is viewShapeInts[dim] = size to preserve the static shape.

I have kept the e2e Python tests for aten.unflatten and the MLIR tests for the TorchToLinalg conversion of unflatten as well, I think they may be useful for some more coverage that wasn't there before, but open to suggestions on whether or not to keep these.

[zjgarvey]

Thanks for the fix. I'd remove the unrelated tests (unflatten isn't actually related to the code change). Let me know when you'd like me to take another look and we can get it merged.

[raayandhar]

Thanks for the fix. I'd remove the unrelated tests (unflatten isn't actually related to the code change). Let me know when you'd like me to take another look and we can get it merged.

Thanks for the feedback - I think it should be good for a look now.