In 71635cb and 357a1d3 we updated the endpoint and profile translators
to prevent backpressure from stalling the informer tasks. This change
updates the endpoint profile translator with the same fix, so that
updates are buffered and can detect when when a gRPC stream is stalled.
Furthermore, the update method is updated to use a protobuf-aware
comparison method instead of using serialization and string comparison.
A test is added for the endpoint profile translator, since none existed
previously.
Oliver Gould