RFR: 8213347: [JVMCI] remove use of reflection in JVMCI

[Doug Simon]

The use of reflection in jdk.vm.ci.services.Services and jdk.vm.ci.services.internal.ReflectionAccessJDK comes from the original JDK 8 based JVMCI code where care had to be taken that JVMCI could be compiled on JDK 8. This use of reflection is no longer necessary since JDK 9 and this webrev removes it.

The webrev also includes some minor Checkstyle related clean ups that I noticed when editing the code in Eclipse.

https://bugs.openjdk.java.net/browse/JDK-8213347
http://cr.openjdk.java.net/~dnsimon/8213347

-Doug