Add test for TCP getpeername
Add test for TCP getpeername

This doesn't appear to be covered by any existing tests. Check that the peer
address for a connected TCP socket matches the local address for the
corresponding accepted socket, and vice-versa.

Fixes #8020

PiperOrigin-RevId: 477186443

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor