Merge JDK-8220154 initial metal implementation patch to the jdk sandbox branch

Engineers from JetBrains have provided initial Metal implementation for basic primitive rendering and image rendering. (See JDK-8220154)
This is a work in progress contribution.

At the same time, we have been working on Metal Rendering Implementation PoCs in http://hg.openjdk.java.net/jdk/sandbox/branches under branch named metal-prototype-branch

The goal of this task is to merge the patch provided by JetBrains with jdk sandox metal-prototype-branch

This will enable working out of a common repository in immediate future.