Inconsistent equality for WrappedArray.ofRef

```
Array(Int.box(1)).toSeq == Array(Double.box(1.0)).toSeq
```
is `false` in `2.12.2 +` and is `true` in `2.11.x , 2.12.0, 2.12.1`

This behavior change is introduced by scala/scala#5551 and effectively this merged one scala/scala#5607 .