[performance] TreeViewer: disable redraw during long operations

improves for example Problems View sort time

Author: EcljpseB0T

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java

@@ -363,7 +363,9 @@ void preservingSelection(Runnable updateCode, boolean reveal) {
 		// updateCode.run():
 		insidePreservingSelection = true;
 		try {
+			tree.setRedraw(false);
 			super.preservingSelection(updateCode, reveal);
+			tree.setRedraw(true);
 		} finally {
 			insidePreservingSelection = false;
 		}