JEP draft: Remove Shark compiler

[Roman Kennke]

I have drafted a JEP with the intention to remove the Shark compiler:

https://bugs.openjdk.java.net/browse/JDK-8189173

I would like to get some opinions here before I submit this JEP for 
real. In particular:

- If anybody has a need for Shark
- If anybody wants to step up to maintain it

speak up now!

Further, if you have anything that is missing or needs to be changed in 
the JEP draft, please let me know.

Thanks,

Roman