Add minimal test case for issue ponylang#1222, solved by ponylang#1232. (ponylang#1233)

Author: jemc

minimal-cases/issue-1222/1222.pony

@@ -0,0 +1,16 @@
+use "collections"
+
+actor Main
+  new create(env: Env) =>
+    var list = List[I32]
+
+    while list.size() < 2 do
+      env.out.print("could be infinite loop if the for loop is optimized out")
+
+      for d in Range[I32](0, 2) do
+        env.out.print("running for loop...")
+        list.push(d)
+      end
+    end
+
+    env.out.print("finished!")