Review Request: 8005694: build-infra: Cleanup of misc changes in build-infra

[Erik Joelsson]

There are a couple of minor changes in build-infra that haven't been 
merged to jdk8/build yet. All are small and insignificant on their own.

* Removal of redundant package entries in jar exclude lists. Also 
sorting the lists to make it easier to spot redundant packages in the 
future.
* Removal of unnecessary source file in native compilation
* Cleaned up comment about code exclusion in CompileJavaClasses.gmk

Not urgent but would be convenient to get in to reduce diff between 
jdk8/build and build-infra/jdk8.

http://cr.openjdk.java.net/~erikj/8005694/webrev.jdk.01/

/Erik