fix corner cases in rename & varify (#4955)

fixes #4954

lib/compress.js

@@ -8604,6 +8604,8 @@ merge(Compressor.prototype, {
                         if (def.scope === scope) return;
                         def.scope = scope;
                         scope.variables.set(def.name, def);
+                        scope.enclosed.push(def);
+                        scope.var_names()[def.name] = true;
                     }),
                     value: defn.value,
                 });