Fix nested classes case in no-ember-super-in-es-classes (#2071)

* A failing test for no-ember-super-in-es-classes

This rule incorrectly fails on the following code:

```js
class Foo {
  bar() {
    Baz.reopen({
      quux() {
        this._super();
      },
    });
  }
}
```

* Add a fix proposal

* boolean instead

* lint

* fixup

lib/rules/no-ember-super-in-es-classes.js

@@ -1,5 +1,26 @@
 'use strict';
 
+function isDirectlyInClass(node) {
+  let currentNode = node.parent;
+  let inFunctionAlready = false;
+
+  while (currentNode) {
+    if (currentNode.type === 'MethodDefinition') {
+      return true;
+    } else if (currentNode.type === 'FunctionExpression') {
+      if (inFunctionAlready) {
+        return false;
+      } else {
+        inFunctionAlready = true;
+      }
+    }
+
+    currentNode = currentNode.parent;
+  }
+
+  return false;
+}
+
 /** @type {import('eslint').Rule.RuleModule} */
 module.exports = {
   meta: {
@@ -19,6 +40,10 @@ module.exports = {
       'MethodDefinition MemberExpression[object.type="ThisExpression"][property.name="_super"]'(
         node
       ) {
+        if (!isDirectlyInClass(node)) {
+          return;
+        }
+
         context.report({
           node,
           message: "Don't use `this._super` in ES classes; instead, you should use `super`",

tests/lib/rules/no-ember-super-in-es-classes.js

@@ -18,6 +18,9 @@ eslintTester.run('no-ember-super-in-es-classes', rule, {
     'EmberObject.extend({ init() { this._super(); } })',
     'EmberObject.extend({ init(a, b) { this._super(a, b); } })',
     'EmberObject.extend({ init() { this._super(...arguments); } })',
+    'class Foo { bar() { Baz.reopen({ quux() { this._super(); } }); } }',
+    'class Foo { bar() { return function() { this._super(); }; } }',
+    'class Foo { bar() { return { baz() { this._super() } }; } }',
   ],
   invalid: [
     {
@@ -70,5 +73,19 @@ eslintTester.run('no-ember-super-in-es-classes', rule, {
         { message: "Don't use `this._super` in ES classes; instead, you should use `super`" },
       ],
     },
+    {
+      code: 'class Foo { init() { return { a: this._super() }; } }',
+      output: 'class Foo { init() { return { a: super.init() }; } }',
+      errors: [
+        { message: "Don't use `this._super` in ES classes; instead, you should use `super`" },
+      ],
+    },
+    {
+      code: 'class Foo { init() { return () => { this._super(); }; } }',
+      output: 'class Foo { init() { return () => { super.init(); }; } }',
+      errors: [
+        { message: "Don't use `this._super` in ES classes; instead, you should use `super`" },
+      ],
+    },
   ],
 });