Introduce a way to enable JVM intrinsics from command-line.

Right now, there's no way to introduce experimental intrinsics which are turned off by default and let users enable them on their side.

There's -XX:DisableIntrinsic= present to *disable* intrinsics. Instead of introducing -XX:EnableIntrinsic= equivalent, it would be nice to have a new option which supersede both and supports both enabling and disabling arbitrary set of intrinsics. As an example:
  -XX:ControlIntrinsic=+_dabs,-_fabs,-_getClass

It makes sense to require -XX:+UnlockExperimentalVMOptions when enabling intrinsics.