Cannot 'export default' abstract, ambient class or interface

```
export default abstract class B {

}
```

By the way, the same with

```
export default declare class B {

}
```

Seems to be a parser bug

Start by reproducing the abstract and ambient class examples in the issue and inspect the parser behavior for those declarations. The work is done when `export default abstract class B` and `export default declare class B` are accepted, along with the reported interface case.

Written by the indexing model from the issue text.