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