Fix Arm64 BE to correctly handle divide by zero
Fix Arm64 BE to correctly handle divide by zero

Update the Jit's Arm64 backend to handle divide by zero in the same
way as Linux Kernel eBPF.  That is:
 * Divide by zero has a result of zero.
 * Modulous by zero has a result of the dividend.

This makes several functions unused.  These have been '#if 0'ed out as
they may be useful in the future.

Signed-off-by: Matthew Gretton-Dann <17bce06e4c7e20e6375a20ae89604c2bf650e2c0@arm.com>

iovisor/ubpf,iovisor/ubpf,iovisor/ubpf,iovisor/ubpf