Rollup merge of #141818 - mati865:dont-create-msi-from-non-windows, r=Kobzol

Don't create .msi installer for gnullvm hosts

WIX toolset works only on Windows hosts, but gnullvm doesn't have host toolchain yet. To get out of this loop, we will create a single release without MSI installer.

Split out from: rust-lang/rust#140772

Author: fmease