While testing #24510 I noticed that 32 bit syscalls were incorrectly being
blocked and we did not have a test for this, so adding one.
This is only tested on amd64 as it is the only architecture that
reliably supports 32 bit code execution, others only do sometimes.
There is no 32 bit libc in the buildpack-deps so we cannot build
32 bit C code easily so use the simplest assembly program which
just calls the exit syscall.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
