src/vs/base/node/shell.ts/getSystemShellWindows
async function getSystemShellWindows(): Promise<string> {
	if (!_TERMINAL_DEFAULT_SHELL_WINDOWS) {
		_TERMINAL_DEFAULT_SHELL_WINDOWS = (await getFirstAvailablePowerShellInstallation())!.exePath;
	}
	return _TERMINAL_DEFAULT_SHELL_WINDOWS;
}