Init nativeZoom of Tracker on creation

As one constructor of Tracker is not calling the super constructor the nativeZoom attribute must be set here as well. As it only has the display as reference, the zoom of the display (currently equal to primary monitor zoom) will be used.

Contributes to eclipse-platform#62 and eclipse-platform#131

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Tracker.java

@@ -142,6 +142,7 @@ public Tracker (Display display, int style) {
 	}
 	this.style = checkStyle (style);
 	this.display = display;
+	this.nativeZoom = display.getDeviceZoom();
 	reskinWidget ();
 }