java: reenable balloon

All fixes for all (known) problems with the balloon are now in the tree.
Reenable it.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
api/aarch64: add alltypes.h.sh script and first headers

add alltypes.h.sh, and first headers in bits/

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>