[aarch64-port-dev ] System.arraycopy() intrinsics

[Andrew Haley]

> Ok, I see what you are saying now. The codeblob lookup allows you to use
> a relative branch, avoiding having to load an absolute address. That
> more than justifies any cost associated with doing the lookup. I will
> drop my proposed changes and do the same as you in the C2 back end.

I'll create a macro that handles blrt(address, intargs, fpargs, type) and
does the Right Thing as efficiently as possible.  This keeps the slightly
icky logic in one place.

Andrew.