Change comparison ops result dtype to bool [Part1] (#20767)
Summary:
This is the first part of the planned changes to change the comparison operations result tensor dtype from Byte to Bool. You can see the whole list of changes (not cleaned up) [here](https://github.com/pytorch/pytorch/pull/19332). As the PR is too big for a single review im breaking it into pieces.
**Changes in this PR:**
1. Enable these methods for bool tensors:
- maskedSelect
- maskedSelectBool
- bitand
- cbitand
- bitor
- cbitor
- bitxor
- cbitxor
- sign
- equal
- neg
2. Add bool clause for the TH version of sign method.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20767
Differential Revision: D15436446
Pulled By: izdeby
fbshipit-source-id: 8d2494b5f4873cd79c7f1a40d2cb045cadfad51a
