new JVMCI binaries

[Roland Schatz]

Hi,

We have released version 0.19 of the JVMCI JDK 8 binaries. You can 
download the Oracle JDK build from OTN [1].
OpenJDK builds of the new version can be downloaded from github [2].

The new version contains backports of changes from JDK-9, including a 
minor API change.

Starting from graal-core revision 
4c735d3ab78edda879c4169d7af5eec04e40e2a5, the minimum required JVMCI 
version is 0.19.

- Roland

[1] 
http://www.oracle.com/technetwork/oracle-labs/program-languages/downloads/index.htm
[2] https://github.com/dougxc/openjdk8-jvmci-builder/releases