All Graal tests pass on AArch64

[Andrew Haley]

... except the truffle ones, which I've excluded.


So I'm going to do a cleanup pass on the aarch64_graal_misc_fixes
branch, hopefully get that pulled into master, and then fix the
Truffle bugs.

Once that's done I'll look at code quality.  There are quite a few
examples of poor code generation.  It would be nice to get Graal
somewhere near C2, but that will require some serious work on
vectorization.

Andrew.