AArch64 Graal Port

[D.Sturm]

Hey,
I'd like to contribute my work on a AArch64 port.

This currently does not compile since I'm still in the progress of porting
all the changes since I last touched the code about a year ago.

Christian Thalinger proposed that I contribute the code nevertheless, with
him getting it into a compilable state so that other volunteers can
contribute to it as well.

Link: http://cr.openjdk.java.net/~twisti/graal-aarch64/webrev/

-Daniel