-release 8 causes java.time.Instant to have a fictitious constructor

On Java 9+:

```shell
% scala -release 8
scala> new java.time.Instant
java.lang.NoSuchMethodError: java.time.Instant: method 'void <init>()' not found
  ... 34 elided
```

This is the same issue as https://github.com/scala/bug/issues/12565 which was fixed by https://github.com/scala/scala/pull/9981