RFR: 8156835: [JVMCI] clean up and minimize JVMCI

[Doug Simon]

I had forgotten to re-apply the removal of UnsafeUtil from https://bugs.openjdk.java.net/browse/JDK-8156759 to 8156835. I’ve applied it now and updated the webrev.

> On 13 May 2016, at 21:54, Doug Simon <doug.simon at oracle.com> wrote:
> 
> 
>> On 13 May 2016, at 18:21, Igor Veresov <igor.veresov at oracle.com> wrote:
>> 
>> Looks ok
> 
> Thanks for the review.
> 
> -Doug
> 
>>> On May 13, 2016, at 4:40 AM, Doug Simon <doug.simon at oracle.com> wrote:
>>> 
>>> Please review this RFE that makes minor changes to clean up and minimize JVMCI.
>>> 
>>> All jtreg tests pass as do all Graal tests.
>>> 
>>> https://bugs.openjdk.java.net/browse/JDK-8156835
>>> http://cr.openjdk.java.net/~dnsimon/8156835
>>> 
>>> -Doug
>> 
>