jest-dom/prefer-empty wrong detection, and wrong fix.

- `eslint-plugin-jest-dom` version: 3.0.1
- `node` version: 12.16.1
- `npm` version: 6.13.4

Broken fix and detection
This is detected as error
```ts
const DONT_KNOW_TEXT = "Don't know"
expect(textarea.innerHTML).toBe(DONT_KNOW_TEXT)
```
Fixes to
```ts
expect(textarea).toBeEmpty()
```