Enabled mul for bool tensors on CUDA (#21771)
Summary:
Enable mul_cuda for bool tensors.
This is a helper PR to fix a [test failure](https://circleci.com/gh/pytorch/pytorch/1992191?utm_campaign=vcs-integration-link&utm_medium=referral&utm_source=github-build-link) in the other [PR](https://github.com/pytorch/pytorch/pull/21113).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21771
Differential Revision: D15883737
Pulled By: izdeby
fbshipit-source-id: 4c39644bbe8e80da4d14570862589944285d4bfe
