The endpoint controllers responded to Pod changes by trying to figure
out if the generated endpoint resource would change, rather than just
checking if the Pod had changed, but since the set of Pod fields that
need to be checked depend on the Service and Node as well, the code
ended up only checking for a subset of the changes it should have.
In particular, EndpointSliceController ended up only looking at IPv4
Pod IPs when processing Pod update events, so when a Pod went from
having no IP to having only an IPv6 IP, EndpointSliceController would
think it hadn't changed.
This was an oversight in the initial EndpointSlice release. This update
will ensure that Endpoints and EndpointSlices use the same logic to set
the Hostname attribute.
