wip for some illumos-aarch64 bits.

• dis_aarch64.c - copy to usr/src/lib/libdisasm/common/dis_aarch64.c
• tests/ - copy into usr/src/test/util-tests/tests/dis/aarch64/
• usr_src.diff - apply to usr/src

Sorry, the usr_src.diff has a bunch of stuff not relevant for the disasm, I'll try to clean it up at some point.