Cleanup _parent, _dom and __hooks after unmount (#3709)

* cleanup _parent, __hooks and _dom when unmounting

* set listeners

* try out perf impact

* Update index.js

* fix test

* add _component removal

* Update index.js

* Update suspense.js

hooks/src/index.js

@@ -125,6 +125,7 @@ options.unmount = vnode => {
 				hasErrored = e;
 			}
 		});
+		c.__hooks = undefined;
 		if (hasErrored) options._catchError(hasErrored, c._vnode);
 	}
 };

mangle.json

@@ -25,6 +25,7 @@
   "props": {
     "cname": 6,
     "props": {
+      "$_listeners": "l",
       "$_cleanup": "__c",
       "$__hooks": "__H",
       "$_list": "__",

src/diff/index.js

@@ -512,6 +512,7 @@ export function unmount(vnode, parentVNode, skipRemove) {
 		}
 
 		r.base = r._parentDom = null;
+		vnode._component = undefined;
 	}
 
 	if ((r = vnode._children)) {
@@ -522,11 +523,13 @@ export function unmount(vnode, parentVNode, skipRemove) {
 		}
 	}
 
-	if (!skipRemove && vnode._dom != null) removeNode(vnode._dom);
+	if (!skipRemove && vnode._dom != null) {
+		removeNode(vnode._dom);
+	}
 
 	// Must be set to `undefined` to properly clean up `_nextDom`
 	// for which `null` is a valid value. See comment in `create-element.js`
-	vnode._dom = vnode._nextDom = undefined;
+	vnode._parent = vnode._dom = vnode._nextDom = undefined;
 }
 
 /** The `.render()` method for a PFC backing instance. */