[win32] Refactor path to support multiple handles

This commit refactors Path in the win32 implementation to better
support multiple handles for different zoom settings of a Path when
monitor-specific scaling is enables. The previous implementation
only applied adaptions on the path to the initial handle and relied
on the path not to be changed after usage. This doesn't cover all
scenarios and can lead to incompletely rendered path when reusing Path
object over different zoom settings.

Author: akoch-yatta

bundles/org.eclipse.swt/Eclipse SWT Tests/win32/org/eclipse/swt/graphics/PathWin32Tests.java

@@ -13,6 +13,7 @@
  *******************************************************************************/
 package org.eclipse.swt.graphics;
 
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.util.*;
@@ -49,9 +50,11 @@ public void testHandlesExistForEachZoomLevelInHashMap() {
 		DPIUtil.setDeviceZoom(zoom);
 		Path path = new Path(display);
 		path.addArc(0, 0, 10, 10, 0, 90);
+		path.getHandle(zoom);
+		assertTrue("zoomLevelToHandle should contain initial zoom's handle", path.toString().contains(zoom + "="));
+		assertFalse("zoomLevelToHandle should not contains scaled handle", path.toString().contains(scaledZoom + "="));
 		path.getHandle(scaledZoom);
-		assertTrue("zoomLevelToHandle contains scaled handle", path.toString().contains(scaledZoom + "="));
-		assertTrue("zoomLevelToHandle contains initial zoom's handle", path.toString().contains(zoom + "="));
+		assertTrue("zoomLevelToHandle should contain scaled handle", path.toString().contains(scaledZoom + "="));
 	}
 
 	@Test