randn and normal_ for complex tensors (#34037)
Summary:
1. randn and normal_ methods will work for complex tensors after this PR
2. added an internal function for viewing complex tensors as float tensors which enables us to reuse functions defined for float tensors for complex tensors with change in arguments passed(like size, standard deviation in case of normal_). currently the resultant new float tensor doesn't share the storage with the input complex tensor which means that the version counter wouldn't be updated if any function is called on this resultant tensor, but once the dtype entry is removed from the storage class, this issue will be resolved.
Side notes:
1. didn't add a separate header for the util functions because of this issue https://github.com/pytorch/pytorch/issues/20686#issuecomment-593002293
2. we should eventually have a public API method view_complex_as_float once (2) mentioned above gets resolved
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34037
Differential Revision: D20221793
Pulled By: anjali411
fbshipit-source-id: a78f5e83d6104e2f55e0b250c4ec32e8d29a14eb
