The handling of downstreamLocalAddress and downstreamRemoteAddress is messy and unclear. Audit uses of the address on both the connection and StreamInfo. Clean up code so it is easier to understand.

• Specifically, the addresses are set twice on the connection StreamInfo, once before listener filters are run and once after. Try to find a better way to handle this.
• HCM sets the downstream address before doing XFF handling. Can this be removed?