8258805: Japanese characters not entered by mouse click on Windows 10

Reviewed-by: aivanov

src/java.desktop/windows/classes/sun/awt/windows/WInputMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -360,6 +360,11 @@ public void deactivate(boolean isTemporary)
         }
         isActive = false;
         hasCompositionString = isCompositionStringAvailable(context);
+
+        // IME is going to be disabled commit the composition string
+        if (hasCompositionString) {
+            endComposition();
+        }
     }
 
     /**