The static JavaNioAccess nioAccess field (introduced by JDK-8234049) in VarHandleByteArrayAs* should be final. It would probably also make sense to move it to VarHandleByteArrayBase.

This is not a problem for inlining because there's only a single implementor of that interface, but it'll result in an unnecessary field load and null check.

```
final class VarHandleByteArrayAsInts extends VarHandleByteArrayBase {
    static JavaNioAccess nioAccess = SharedSecrets.getJavaNioAccess();
```