8261231: Windows IME was disabled after DnD operation

Reviewed-by: kizune, serb

src/java.desktop/windows/native/libawt/windows/awt_Toolkit.cpp

@@ -3215,10 +3215,12 @@ LRESULT AwtToolkit::InvokeInputMethodFunction(UINT msg, WPARAM wParam, LPARAM lP
      * function once the DND is active; otherwise a hang is possible since DND may wait for
      * the IME completion.
      */
+    CriticalSection::Lock lock(m_inputMethodLock);
     if (isInDoDragDropLoop) {
-        return SendMessage(msg, wParam, lParam);
+        SendMessage(msg, wParam, lParam);
+        ::ResetEvent(m_inputMethodWaitEvent);
+        return m_inputMethodData;
     } else {
-        CriticalSection::Lock lock(m_inputMethodLock);
         if (PostMessage(msg, wParam, lParam)) {
             ::WaitForSingleObject(m_inputMethodWaitEvent, INFINITE);
             return m_inputMethodData;