test: Improve error reporting when wait fails
test: Improve error reporting when wait fails

When the test fails because it is waiting for containers to terminate,
add this information into the error that is reported so that developers
can more easily debug the issue that's occurring.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

cilium/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium