Use Server 2022 in CI for mingw jobs From my [previous testing](https://github.com/rust-lang/rust/issues/92948#issuecomment-2077771347), there is nothing blocking using Server 2022 for the Windows MinGW jobs. This change: * Adds new `os` entries for Server 2022. * Renamed the Server 2019 `os` entries (as we'll be removing these over time). * Moves the mingw jobs to Server 2022 and leaves the msvc jobs on Server 2019. Partially fixes #92948