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

[Christian Thalinger]

> 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.
> 
> https://bugs.openjdk.java.net/browse/JDK-8156759

The JIRA issue states:

"Only Graal uses the context functionality of JVMCIError so it will move it Graal.”

But there is more value to JVMCIError than just the context functionality.  Having a separate JVMCI exception class can be useful when catching exceptions.

> http://cr.openjdk.java.net/~dnsimon/8156759

> 
> -Doug