runtime: add arm64 version of AES hash code

    
    Rewrite the arm64 AES hashing code from gc assembler to C code using
    intrinsics.  The resulting code generates the same hash code for the
    same input as the gc code--that doesn't matter as such, but testing it
    ensures that the C code does something useful.
    
    Reviewed-on: https://go-review.googlesource.com/138535

From-SVN: r264771

gcc/go/gofrontend/MERGE

-f4a224ec481957ca4f14d0e8cc4fe59cc95b3a49
+013a9e68c9a31f888733d46182d19f9e5d956f27
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.