Handle `CallExpression` for debug macros.

Currently, we are handling only `ExpressionStatement`'s for debug macro replacement. Unfortunately, the following do not get processed (since they do not include an `ExpressionStatement`):

```js
function foo() {
return assert(false, 'derp'); // ReturnStatement
}

let qux = () => assert(false, 'herp'); // ArrowFunctionExpression
```

This is the underlying issue in https://github.com/babel/ember-cli-babel/issues/168.

首先跟踪 ExpressionStatement 的调试宏替换处理，并将其与示例中所示的 ReturnStatement 和 ArrowFunctionExpression 内的 CallExpression 情况进行比较。确认两个 assert 调用都会被处理，并为这两种形式添加或运行覆盖率；完成的标准是两个示例都不会被跳过。

由索引模型根据 Issue 内容生成。