Added tests; improved test output; code clean-up

pkg/analyzer/lib/src/generated/constant.dart

Index: pkg/analyzer/lib/src/generated/constant.dart
diff --git a/pkg/analyzer/lib/src/generated/constant.dart b/pkg/analyzer/lib/src/generated/constant.dart
index d8371da26520bd6e4e889386dccba791ddf4e4c8..0f1d7e945fa53f412e2b14798d7c4dbf48d42480 100644
--- a/pkg/analyzer/lib/src/generated/constant.dart
+++ b/pkg/analyzer/lib/src/generated/constant.dart
@@ -1321,8 +1321,8 @@ class ConstantFinder extends RecursiveAstVisitor<Object> {
                 element is FieldElement &&
                 node.isFinal &&
                 !element.isStatic)) {
-      if (node.element != null) {
-        constantsToCompute.add(node.element);
+      if (element != null) {
+        constantsToCompute.add(element);
       }
     }
     return null;