Add const qualifier to returned pointers in MockIp and MockResolvedAddress (#12573)
Add const qualifier to returned pointers in MockIp and MockResolvedAddress (#12573)

Compared to their superclasses, the MockIp and MockResolvedAddress
classes dropp the const qualifier from the pointers they return.
Since the non-mock class implementing these methods return const
pointers, it’s difficult to use non-mock classes with these mocks
without resorting to hacks like const_cast.

Signed-off-by: Justin Mazzola Paluska <85c2c197ae5706efbb51578cce8bd5739cb2660e@google.com>
lizan/envoy,lizan/envoy,envoyproxy/envoy-wasm,lyft/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,lyft/envoy,lizan/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy