Migrate from AppVeyor to Travis CI Windows?

[dwijnand]

With Travis CI adding support for Windows (https://blog.travis-ci.com/2018-10-11-windows-early-release) should we transition from AppVeyor to Travis CI for Windows testing too?

Any feels for or against?

[dwijnand]

One benefit is I seem to be able to restart Travis CI jobs, but not AppVeyor jobs.

[Arzte]

An argument for it is that it would mean everything would be in one place, all the builds together.

[alexcrichton]

This seems like it's worthwhile to test for! The main reason for us I believe is that we have more capacity on Travis than AppVeyor so builds may finish more quickly. Should be fine to test out a PR regardless!

[Eh2406]

People are reporting that it is nearly unusable slow do to rust-lang/rustup#998 (comment)
It is worth a shot, but I am not hopefully until that is fixed.

[dwijnand]

Hmm. OK, then let's park this for now.

[dwijnand]

Once rust-lang/rustup#998 is fixed, resolving this might allow resolving downstream issues, like #4495.

[slonopotamus]

rust-lang/rustup#998 is now fixed