pkg/host: don't enable binfmt_misc on non-linux

The csource options lack any relation to the tested OS,
while they do depend on the tested OS (most are linux-specific).
As the result we enable binfmt_misc, but its setup fails on anything
other than linux. As a work-around don't enable binfmt_misc on non-linux.

pkg/host/host.go

@@ -121,7 +121,7 @@ func Setup(target *prog.Target, features *Features, featureFlags csource.Feature
 	if features[FeatureFaultInjection].Enabled {
 		args = append(args, "fault")
 	}
-	if featureFlags["binfmt_misc"].Enabled {
+	if target.OS == "linux" && featureFlags["binfmt_misc"].Enabled {
 		args = append(args, "binfmt_misc")
 	}
 	_, err := osutil.RunCmd(time.Minute, "", executor, args...)