Rule sortKeys breaks type format when declared before an object

When `eslint-plugin-flowtype` try to format the following code:

```js
type FooType = {|
c: number,
b: number,
a: number
|}

const Dummy = {
a: true
}
```

It generates the following result:

```js
type FooType = {|
a: number
|}

const Dummy,
b: number,
a: number
|}

const Dummy = {
a: true
}
```

I created [a branch](https://github.com/gajus/eslint-plugin-flowtype/compare/master...luisfmsouza:chore/sort-keys) with this broken scenario.

Reproduce the issue with the Flow type and object shown in the report, then inspect the sortKeys rule and the comparison branch linked in the issue. Done means the rule sorts the properties without moving type members into the following const declaration, while preserving valid Flow and JavaScript syntax.

Written by the indexing model from the issue text.