RFR: 8147599: [JVMCI] simplify code installation interface

[Christian Thalinger]

Looks good.

> On Jan 20, 2016, at 3:35 AM, Roland Schatz <roland.schatz at oracle.com> wrote:
> 
> Hi,
> 
> Please review this change to the JVMCI code installation interface:
> 
> webrev: http://cr.openjdk.java.net/~rschatz/JDK-8147599/webrev.00/
> jira: https://bugs.openjdk.java.net/browse/JDK-8147599
> 
> The new classes in the jdk.vm.ci.code.site package used to be inner classes in the removed CompilationResult class, no actual code changes there.
> 
> Thanks,
> Roland