--raw-command does not launch with an interpreter on Windows

Thank you very much for this application 😺 .

Right now there doesn't seem to be a way to pass args to a windows bash shell. When calling my script with how exec presently works Windows returns that my script isn't a valid win32 application (which it's right).

STR is fairly clean, just `go run gotest.tools/gotestsum@latest --junitfile unit-tests.xml --format pkgname --raw-command ./profile.sh -- ./...` on Windows.

Using something like https://github.com/mattn/go-shellwords may be helpful for parsing these strings into commands with args and similar. Wrapping the run with `bash -c profile.sh` invokes okay, but the args don't make it through.

Start by locating the --raw-command handling used by the provided gotestsum invocation and reproduce the command on Windows. The work is done when a script can launch through an interpreter and its arguments reach the script, while the existing go test arguments still work.

Written by the indexing model from the issue text.