RFR(M):8167065: Add intrinsic support for double precision shifting on x86_64

[Alan Bateman]

On 20/12/2019 22:19, Vladimir Kozlov wrote:
> We should have added core-libs to review since you modified 
> BigInteger.java.
>
This adds Objects.checkFromToIndex checks in the middle of several 
supporting methods. Is IOOBE really possible in these cases or are these 
stand in for always-on asserts to ensure the instrinic is never used 
when the preconditions aren't satisfied?

-Alan