Add newaxis to torch aliases

[rgommers]

Closes gh-64

[rgommers]

Will add a corresponding test case to array-api_tests as well (see data-apis/array-api-tests#198).

[asmeurer]

Looks good. Merging might be blocked on #65 though.

[rgommers]

This was green before, and gh-65 is unrelated and should not be blocking. No idea why the fft tests are failing now, probably another case of "should use derandomize". Either way, let's merge this?

[asmeurer]

We'll have to fix the CI before we release at least.