Regex does not support quotes with \Q..\E

The following regex matches in Scala

```
scala> "^\\Qmember\\E.*\\Q\\E$".r.pattern.matcher("member0").matches
res0: Boolean = true
```

but not in Scala-js

```
scala.scalajs.js.Dynamic.global.console.log(
  "^\\Qmember\\E.*\\Q\\E$".r.pattern.matcher("member0").matches
)

.. 
> false
```
