Improve behavior when sending to closed connection

- On Unix, this would previously kill the Yuzu process with SIGPIPE.
  Send MSG_NOSIGNAL to opt out of this.

- Add support for the proper error code in this situation, EPIPE.

- Windows has nonstandard behavior in this situation; translate it to
  the standard behavior.  Kind of pointless, but isn't it nice to be
  correct?

src/core/hle/service/sockets/sockets.h

@@ -18,7 +18,9 @@ enum class Errno : u32 {
     AGAIN = 11,
     INVAL = 22,
     MFILE = 24,
+    PIPE = 32,
     MSGSIZE = 90,
+    CONNABORTED = 103,
     CONNRESET = 104,
     NOTCONN = 107,
     TIMEDOUT = 110,