Think about using mingw-w64 with dwarf exception support for rustc cross-compilation for 32bit Windows

Our workaround we currently use to cope with issues cross-compiling rustc for 32bit Windows is not upstreamable (see: https://github.com/rust-lang/rust/pull/55444 for the arguments). We could think about compiling with a mingw-w64 using dwarf exception support instead, see: (https://github.com/rust-embedded/cross/blob/master/docker/mingw.sh).

However, we should take into account that we want to switch to a mingw-w64/clang-based toolchain soon and should start looking into this ticket not before the other (legacy/trac#28238 (moved)) is done.