.gitignore: Add missing test programs
/test/send_recvmsg
/test/shared-wq
/test/short-read
+/test/shutdown
/test/sigfd-deadlock
/test/socket-rw
+/test/socket-rw-eagain
/test/splice
/test/sq-full
/test/sq-full-cpp
/test/sq-poll-kthread
+/test/sq-poll-share
/test/sq-space_left
/test/statx
/test/stdout
