Support for JDK 9 and 10

[jkutner]

The Heroku Java Agent should support JDK 9 and 10. With the latest release (2.0) the following error may be generated:

*** java.lang.instrument ASSERTION FAILED ***: "!errorOutstanding" with message transform method call failed at JPLISAgent.c line: 884
Exception in thread "Heroku MemoryAgent Timer" java.lang.IllegalAccessError: class com.heroku.agent.MemoryAgent$Reporter$LazyJMX (in unnamed module @0x2bc9f23c) cannot access class sun.management.HotspotInternal (in module java.management) because module java.management does not export sun.management to unnamed module @0x2bc9f23c