Fix Unix Sleep for Wrong Time. test=develop (#29953)

PADDLE_RETRY_CUDA_SUCCESS used wrong sleep time so it can cause timeout in unittest. This PR fixed it.

After we searched the doc in https://pubs.opengroup.org/onlinepubs/7908799/xsh/unistd.h.html, the time unit of sleep in unistd.h takes "seconds", usleep takes "microseconds", Sleep in windows.h takes "milliseconds".

paddle/fluid/platform/enforce.h

@@ -932,7 +932,7 @@ inline void retry_sleep(unsigned millisecond) {
 #ifdef _WIN32
   Sleep(millisecond);
 #else
-  sleep(millisecond);
+  usleep(millisecond * 1000);
 #endif
 }