Stop printing when stdout is closed.

runtime/bin/eventhandler_macos.cc

Index: runtime/bin/eventhandler_macos.cc
diff --git a/runtime/bin/eventhandler_macos.cc b/runtime/bin/eventhandler_macos.cc
index a6554c9fc7e33b21045b780ee271243b2c82ed01..3008e4712cec52246fa48a825689b65af1732875 100644
--- a/runtime/bin/eventhandler_macos.cc
+++ b/runtime/bin/eventhandler_macos.cc
@@ -235,7 +235,12 @@ void EventHandlerImplementation::HandleInterruptFd() {
         // Close the socket and free system resources.
         RemoveFromKqueue(kqueue_fd_, sd);
         intptr_t fd = sd->fd();
-        sd->Close();
+        if (fd == STDOUT_FILENO) {
+          // If stdout, redirect fd to /dev/null.
+          USE(dup2(open("/dev/null", O_WRONLY), STDOUT_FILENO));
+        } else {
+          sd->Close();
+        }
         socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
         delete sd;
       } else {