Remove unsupported syscall event for setsockopt(*, SOL_SOCKET, SO_OOBINLINE).

Netstack behaves as if SO_OOBINLINE is always set, and was logging an
unsupported syscall event if the app tries to disable it. We don't have a real
use case for TCP urgent mechanisms (and RFC6093 says apps SHOULD NOT use it).

This CL keeps the current behavior, but removes the unsupported syscall event.

Fixes #6123

PiperOrigin-RevId: 378026059

pkg/sentry/socket/netstack/netstack.go

@@ -1798,11 +1798,6 @@ func setSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, nam
 		}
 
 		v := hostarch.ByteOrder.Uint32(optVal)
-
-		if v == 0 {
-			socket.SetSockOptEmitUnimplementedEvent(t, name)
-		}
-
 		ep.SocketOptions().SetOutOfBandInline(v != 0)
 		return nil