idpool: don't initialize ID cache in random order
idpool: don't initialize ID cache in random order

There is no need to initialize the ID cache in random order. All that we
care about is that the IDs are allocated in random order. This is
ensured by (*idCache).allocateID iterating over a map which in Go is
guaranteed to be in random order.

For #10056, this saves the peek allocation of the permutation slice
during initialization, which in the worst case of pkg/identity/allocator
is 512K (64k IDs * sizeof int).

Signed-off-by: Tobias Klauser <9249c549618448e4c699e8032ba6c7f0d7fd4b7f@distanz.ch>

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