Adds arccosh alias for acosh and adds an alias consistency test (#43107)
Summary:
This adds the torch.arccosh alias and updates alias testing to validate the consistency of the aliased and original operations. The alias testing is also updated to run on CPU and CUDA, which revealed a memory leak when tracing (see https://github.com/pytorch/pytorch/issues/43119).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43107
Reviewed By: ngimel
Differential Revision: D23156472
Pulled By: mruberry
fbshipit-source-id: 6155fac7954fcc49b95e7c72ed917c85e0eabfcd
