RFR: 8169331: [JVMCI] incomplete API to MethodParameters attribute

[Doug Simon]

When working on JDK-8168915, I overlooked the need to be able to determine if parameter names are from a class file or are synthesized. Since we only care about non-synthesized names in Graal, JVMCI needs to expose that information.

https://bugs.openjdk.java.net/browse/JDK-8169331
http://cr.openjdk.java.net/~dnsimon/8169331/webrev/

-Doug