Tests fail on new Windows terminal when ran multiple times

[mainrs]

Not sure why but while I was working on the two PRs that got merged the other day (#555, #552), I noticed that running cargo test inside the new Windows terminal fails for a bunch of tests. They seem to pass CI though.

Windows: 10 20H2 (19042.870) rustc: rustc 1.51.0 (2fd73fabe 2021-03-23)

I think the reason is that the tests do not properly reset the terminal after they ran. Alongside that, they have to be run with a single thread to make them all pass. When trying to use the terminal after I ran the tests I always get "rendering artifacts". The lines are messed up, I overwrite stuff when typing that I shouldn't overwrite and similar problems.

Not a problem for CI but might be something that should be investigated (even if it sounds boring :smile: )