testdata/issues: add test case for #240

This uncovered a bug where a cyclical reference between a variant and a resource could lead to incorrect serialization.

Author: ydnar

testdata/issues/issue240.wit

@@ -0,0 +1,17 @@
+package issues:issue240;
+
+interface i {
+	// v refers to r
+	variant v {
+		one(r),
+	}
+
+	// r refers to v
+	resource r {
+		f: func(param: v);
+	}
+}
+
+world w {
+    import i;
+}

testdata/issues/issue240.wit.json

@@ -0,0 +1,105 @@
+{
+  "worlds": [
+    {
+      "name": "w",
+      "imports": {
+        "interface-0": {
+          "interface": {
+            "id": 0
+          }
+        }
+      },
+      "exports": {},
+      "package": 0
+    }
+  ],
+  "interfaces": [
+    {
+      "name": "i",
+      "types": {
+        "r": 0,
+        "v": 2
+      },
+      "functions": {
+        "[method]r.f": {
+          "name": "[method]r.f",
+          "kind": {
+            "method": 0
+          },
+          "params": [
+            {
+              "name": "self",
+              "type": 3
+            },
+            {
+              "name": "param",
+              "type": 2
+            }
+          ],
+          "results": []
+        }
+      },
+      "package": 0
+    }
+  ],
+  "types": [
+    {
+      "name": "r",
+      "kind": "resource",
+      "owner": {
+        "interface": 0
+      },
+      "docs": {
+        "contents": "r refers to v"
+      }
+    },
+    {
+      "name": null,
+      "kind": {
+        "handle": {
+          "own": 0
+        }
+      },
+      "owner": null
+    },
+    {
+      "name": "v",
+      "kind": {
+        "variant": {
+          "cases": [
+            {
+              "name": "one",
+              "type": 1
+            }
+          ]
+        }
+      },
+      "owner": {
+        "interface": 0
+      },
+      "docs": {
+        "contents": "v refers to r"
+      }
+    },
+    {
+      "name": null,
+      "kind": {
+        "handle": {
+          "borrow": 0
+        }
+      },
+      "owner": null
+    }
+  ],
+  "packages": [
+    {
+      "name": "issues:issue240",
+      "interfaces": {
+        "i": 0
+      },
+      "worlds": {
+        "w": 0
+      }
+    }
+  ]
+}

testdata/issues/issue240.wit.json.golden.wit

@@ -0,0 +1,15 @@
+package issues:issue240;
+
+interface i {
+	/// r refers to v
+	resource r {
+		f: func(param: v);
+	}
+
+	/// v refers to r
+	variant v { one(r) }
+}
+
+world w {
+	import i;
+}