ipam/allocator: Add test for no allocator case
ipam/allocator: Add test for no allocator case

This commit adds a new test case for the podcidr package. While at it,
change the test function to verify the actual error, rather than
simplying checking if we hit an error.

Signed-off-by: Chris Tarazi <711c73f64afdce07b7e38039a96d2224209e9a6c@isovalent.com>

tgraf/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium