System.arraycopy

[Deneau, Tom]

Since we cannot handle "foreign calls" in the hsail backend, what is the preferred way to implement System.arraycopy?  Right now, we are deferring to the host and so getting an ArrayCopyCallNode which gets lowered to a graph containing a ForeignCallNode.

I confess to being a little confused with the ArrayCopyNode and Snippets, UnsafeArrayCopyNode and Snippets, ArrayCopyCallNode, etc.

-- Tom