Ava watch does not work with pre-compile option

Please provide details about:

* What you're trying to do

Ava watch mode with this package.

```json
{
"ava": {
"files": [
"src/**/*.test.ts"
],
"typescript": {
"rewritePaths": {
"src/": "build/"
},
"compile": "tsc"
}
}
}
```

* What happened

`ava --watch`

If I change a source file or test file the runner is not restarted. If I do the same with `ts-node/register` it works.

* What you expected to happen

Ava runner should rerun on file change.

ava: 3.15.0