Make JUnit diff order consistent with the default compare diff order

Similar to the refactoring wizard, JUnit diff order was always NOT
following "traditional" Eclipse compare editor diff order (left is
"new", right is "old"), so that "natural" order expected / actual was
inconsistent with the compare editor preference, but it was based on
this preference (via CompareConfiguration).

Now the "natural" order is default, swap the sides in JUNit diff pane to
keep same order in as before left: expected, right: actual.

See eclipse-platform/eclipse.platform#2566
See eclipse-platform/eclipse.platform.ui#3777
See eclipse-platform/eclipse.platform.ui#3776 (comment)

Author: iloveeclipse

org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/CompareResultDialog.java

@@ -254,9 +254,9 @@ protected Control createDialogArea(Composite parent) {
 
 	private Control createPreviewer(Composite parent) {
 	    final CompareConfiguration compareConfiguration= new CompareConfiguration();
-	    compareConfiguration.setLeftLabel(JUnitMessages.CompareResultDialog_expectedLabel);
+	    compareConfiguration.setLeftLabel(JUnitMessages.CompareResultDialog_actualLabel);
 	    compareConfiguration.setLeftEditable(false);
-	    compareConfiguration.setRightLabel(JUnitMessages.CompareResultDialog_actualLabel);
+	    compareConfiguration.setRightLabel(JUnitMessages.CompareResultDialog_expectedLabel);
 	    compareConfiguration.setRightEditable(false);
 	    compareConfiguration.setProperty(CompareConfiguration.IGNORE_WHITESPACE, Boolean.FALSE);
 	    compareConfiguration.setProperty(PREFIX_SUFFIX_PROPERTY, fPrefixSuffix);
@@ -271,7 +271,7 @@ private Control createPreviewer(Composite parent) {
 
 	private void setCompareViewerInput() {
 		if (!fViewer.getControl().isDisposed()) {
-			fViewer.setInput(new DiffNode(new CompareElement(fExpected), new CompareElement(fActual)));
+			fViewer.setInput(new DiffNode(new CompareElement(fActual), new CompareElement(fExpected)));
 			fCompareViewerPane.setText(fTestName);
 		}
 	}