Issue 400: [GTK][Wayland] Unwanted SWT.MouseUp at the end of drag&drop

The reason for adding this code is unclear. MacOS, Windows,
Linux-GTK-X11 and Linux-GTK-Wayland - all of these don't send
`button-release-event` (SWT sends it as `SWT.MouseUp`). So there's not a
single platform that would send it, but for some reason Wayland is
blamed for it and an event is forced there.

The code was added in Bug 510446 in Gerrit 88748 [1] in revision 3,
where revision 2 was on 2017-01-19 and revision 3 was on 2017-01-20. No
relevant discussions occurred on Gerrit or Bug at this time.

This fixes part of problem #1-4 from the snippet (see previous commits)

[1] https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/88784/3

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>

bundles/org.eclipse.swt/Eclipse SWT Drag and Drop/gtk/org/eclipse/swt/dnd/DragSource.java

@@ -502,13 +502,6 @@ void dragEnd(long widget, long context){
 			long selection = GTK.gtk_tree_view_get_selection (widget);
 			GTK.gtk_tree_selection_set_select_function(selection,0,0,0);
 		}
-
-		/*
-		 * send a mouse Up signal for >GTK3.14 as Wayland (support as of 3.14)
-		 * does not trigger a MouseUp/Mouse_release_event on DragEnd.
-		 * See Bug 510446.
-		 */
-		control.notifyListeners(SWT.MouseUp, event);
 	}
 	moveData = false;
 }