metropolis: Lock down visibility rules

This formalizes the package structure introduced by D683.

Test Plan: Pure refactor, CI only.

X-Origin-Diff: phab/D684
GitOrigin-RevId: 574aa14c71faf94f4a5c02a2110e2e3fef7d36ac
diff --git a/metropolis/test/ktest/BUILD b/metropolis/test/ktest/BUILD
index d94831c..38f1f31 100644
--- a/metropolis/test/ktest/BUILD
+++ b/metropolis/test/ktest/BUILD
@@ -13,7 +13,7 @@
     name = "ktest",
     embed = [":go_default_library"],
     pure = "on",
-    visibility = ["//visibility:public"],
+    visibility = ["//metropolis:__subpackages__"],
 )
 
 kconfig_patch(
@@ -53,11 +53,11 @@
 
     cp $$DIR/vmlinux $@
     """,
-    visibility = ["//visibility:public"],
+    visibility = ["//metropolis:__subpackages__"],
 )
 
 filegroup(
     name = "test-script",
     srcs = ["run_ktest.sh"],
-    visibility = ["//visibility:public"],
+    visibility = ["//metropolis:__subpackages__"],
 )
diff --git a/metropolis/test/ktest/init/BUILD.bazel b/metropolis/test/ktest/init/BUILD.bazel
index 4161146..0298a8e 100644
--- a/metropolis/test/ktest/init/BUILD.bazel
+++ b/metropolis/test/ktest/init/BUILD.bazel
@@ -12,5 +12,5 @@
     name = "init",
     embed = [":go_default_library"],
     pure = "on",
-    visibility = ["//visibility:public"],
+    visibility = ["//metropolis:__subpackages__"],
 )