RFR: 8156759: [JVMCI] remove JVMCIError and UnsafeUtil classes

[Doug Simon]

> On 11 May 2016, at 22:54, Christian Thalinger <christian.thalinger at oracle.com> wrote:
> 
> 
>> On May 11, 2016, at 10:19 AM, Doug Simon <doug.simon at oracle.com> wrote:
>> 
>> Please review this change which removes a couple of classes which do not need to be in JVMCI.
>> 
>> I’ve also taken the liberty of including a change that updates the mx Java compliance level for all JVMCI projects to 9 since JDK9 API (e.g., java.lang.reflect.Module) is now used in JVMCI. This means building with mx has been broken since that API usage was introduced. I can pull this out into a separate RFE if necessary but am hoping it can piggy back on this bug.

I’ve removed the above changes from the webrev.

-Doug