Properly sort marker resolution by relevance

Currently the marker resolution is sorted, but markers with the *lowest*
relevance are show on top, and therefore these are selected by default.
This is confusing and gives a bad user experience, also this is the
reverse order than we use when offering the quickfix in the editor
itself.

This now sorts the list that the marker with the highest relevance is on
top and selected by default.

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/QuickFixPage.java

@@ -235,17 +235,27 @@ public Image getImage(Object element) {
 			 */
 			@Override
 			public int compare(Viewer viewer, Object e1, Object e2) {
-				int relevanceMarker1 = (e1 instanceof IMarkerResolutionRelevance)
-						? ((IMarkerResolutionRelevance) e1).getRelevanceForResolution()
-						: 0;
-				int relevanceMarker2 = (e2 instanceof IMarkerResolutionRelevance)
-						? ((IMarkerResolutionRelevance) e2).getRelevanceForResolution()
-						: 0;
-				int c = Integer.compare(relevanceMarker1, relevanceMarker2);
+				int relevanceMarker1 = getRelevance(e1);
+				int relevanceMarker2 = getRelevance(e2);
+				int c = Integer.compare(relevanceMarker2, relevanceMarker1);
 				if (c != 0) {
 					return c;
 				}
-				return ((IMarkerResolution) e1).getLabel().compareTo(((IMarkerResolution) e2).getLabel());
+				return getLabel(e1).compareTo(getLabel(e2));
+			}
+
+			private static String getLabel(Object object) {
+				if (object instanceof IMarkerResolution resolution) {
+					return resolution.getLabel();
+				}
+				return ""; //$NON-NLS-1$
+			}
+
+			private static int getRelevance(Object object) {
+				if (object instanceof IMarkerResolutionRelevance relevance) {
+					return relevance.getRelevanceForResolution();
+				}
+				return 0;
 			}
 		});