Type spread over intersection types doesn't work

This is a:

- [x] Bug Report
- [ ] Feature Request
- [ ] Question
- [ ] Other

Which concerns:

- [x] flow-runtime
- [x] babel-plugin-flow-runtime
- [ ] flow-runtime-validators
- [ ] flow-runtime-mobx
- [ ] flow-config-parser
- [ ] The documentation website

---

### What is the current behaviour?

A type spread over an intersection creates invalid code
```
import t from 'flow-runtime';

type C1 = { type: 'C1' } & { test1: string }

type Err = { id: number, ...C1 }

const v : Err = { id: 10, type: 'C1', test1: 'whatever' }
console.log(t.validate(Err, v).hasErrors())
```

---

### What is the expected behaviour?

To be consistent with Flow's semantics

[Try Flow example](https://flow.org/try/#0C4TwDgpgBAwgjFAvFA3lUkBcUDk8dQC+UAZKuhAM7BzbUBOAlgHYDmRAUBxtAKL30k5RgBNszAK4BbAEYR6AGigA6VfE5QOAYwD2zalABuUbP0HI0o7HAAMSntjxwc9qjUcB3ABYBDYBEN5AkIgA)

---

### Which package versions are you using?

Reproducible on live demo https://codemix.github.io/flow-runtime/#/try