test-vmstate: remove yield_until_fd_readable

The function is not needed anymore now that migration is built on
top of QIOChannel.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/test-vmstate.c

@@ -33,17 +33,6 @@
 static char temp_file[] = "/tmp/vmst.test.XXXXXX";
 static int temp_fd;
 
-/* Fake yield_until_fd_readable() implementation so we don't have to pull the
- * coroutine code as dependency.
- */
-void yield_until_fd_readable(int fd)
-{
-    fd_set fds;
-    FD_ZERO(&fds);
-    FD_SET(fd, &fds);
-    select(fd + 1, &fds, NULL, NULL, NULL);
-}
-
 
 /* Duplicate temp_fd and seek to the beginning of the file */
 static QEMUFile *open_test_file(bool write)