osbase: move test packages under osbase/test

The cmd, freeport and socksproxy packages are only used in tests, and
are also intended to be only used in tests. This change moves these
packages under osbase/test.

Change-Id: I8fe679945990c295bdf822abfce56c25233c4588
Reviewed-on: https://review.monogon.dev/c/monogon/+/4564
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/cli/takeover/e2e/main_test.go b/metropolis/cli/takeover/e2e/main_test.go
index 556f300..c86a48d 100644
--- a/metropolis/cli/takeover/e2e/main_test.go
+++ b/metropolis/cli/takeover/e2e/main_test.go
@@ -25,8 +25,8 @@
 	"golang.org/x/sys/unix"
 
 	"source.monogon.dev/osbase/fat32"
-	"source.monogon.dev/osbase/freeport"
 	"source.monogon.dev/osbase/structfs"
+	"source.monogon.dev/osbase/test/freeport"
 )
 
 var (