Judge tests that read another repository against what the check clones, never the desktop's checkout (issue 432)

Tests that read ../../../mesh-catalog or ../../../mesh-host gave a verdict
that depended on what sat beside the checkout: a stale or dirty sibling
failed them on a desktop, and a missing one skipped them unseen. They now
read the clone the build seat puts in MESH_CHECK_BESIDE, failing when it is
absent there, and elsewhere a copy captured at a named commit.

The skip had hidden that the builder test read a module retired by ADR 0190.
The systemd reading test no longer counts the machine's own environment.d.

testdata/beside/mesh-catalog/modules/mesh-cli/module.json.captured

@@ -0,0 +1,31 @@
+{
+  "module": "mesh-cli",
+  "version": "1",
+  "resources": [
+    {
+      "id": "program",
+      "type": "archive",
+      "artifact": "program",
+      "path": "/usr/local/bin"
+    }
+  ],
+  "shell": [
+    {
+      "for": "zsh",
+      "slot": "normal",
+      "code": "# The operator's command (module mesh-cli, novox/hq ADR 0272): nox is mesh-cli, in interactive zsh only.\n# A script, sudo and a document meant to work everywhere say mesh-cli.\nalias nox=mesh-cli\n"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "program",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/mesh-cli",
+        "binary": "mesh-cli"
+      }
+    ]
+  }
+}