8234107: Several AWT modal dialog tests failing on Linux after JDK-8231991

Summary: Fix off by one in wheel detection logic
Reviewed-by: prr

src/solaris/classes/sun/awt/X11/XBaseWindow.java

@@ -1011,8 +1011,8 @@ public class XBaseWindow {
         int buttonState = 0;
         buttonState = xbe.get_state() & XConstants.ALL_BUTTONS_MASK;
 
-        boolean isWheel = (theButton != XConstants.MouseWheelUp ||
-                           theButton != XConstants.MouseWheelDown);
+        boolean isWheel = (theButton == XConstants.MouseWheelUp ||
+                           theButton == XConstants.MouseWheelDown);
 
         // don't give focus if it's just the mouse wheel turning
         if (!isWheel) {

src/solaris/classes/sun/awt/X11/XConstants.java

@@ -208,8 +208,8 @@ final public class XConstants {
 
     // those should probably be wrapped in a method or such
     // as it may be possible to remap them via x11 configuration files
-    public static final int MouseWheelUp = buttons[4];
-    public static final int MouseWheelDown = buttons[5];
+    public static final int MouseWheelUp = buttons[3];
+    public static final int MouseWheelDown = buttons[4];
 
     /* Notify modes */