fix weird path context state by clearing the context before we visit it

src/babel/traversal/context.js

@@ -34,6 +34,8 @@ export default class TraversalContext {
       if (visited.indexOf(path.node) >= 0) continue;
       visited.push(path.node);
 
+      path.setContext(this.parentPath, this, path.key);
+
       if (path.visit()) {
         stop = true;
         break;