Conv2d shape calculation for meta tensors (#79834)
Fixes #79512
This PR adds support for convolutional meta modules and computes the output shape correctly for some meta input tensor.
Currently in progress, no tests written so far.
**Feature implementations**:
- [x] `Conv1d`
- [x] `Conv2d`
- [x] `Conv3d`
**Tests**:
- [x] `Conv1d`
- [x] `Conv2d`
- [x] `Conv3d`
cc @albanD @anjali411
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79834
Approved by: https://github.com/ezyang, https://github.com/albanD
