Warn about overriding operator== but not hashCode.

dart/tests/compiler/dart2js/analyze_helper.dart

Index: dart/tests/compiler/dart2js/analyze_helper.dart
diff --git a/dart/tests/compiler/dart2js/analyze_helper.dart b/dart/tests/compiler/dart2js/analyze_helper.dart
index c3e6729506de0ff985e053ae43b906bc7decc633..11abc46d87ad379743fd43b586d21a6456fa1ac7 100644
--- a/dart/tests/compiler/dart2js/analyze_helper.dart
+++ b/dart/tests/compiler/dart2js/analyze_helper.dart
@@ -27,6 +27,7 @@ import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.
 
 class CollectingDiagnosticHandler extends FormattingDiagnosticHandler {
   bool hasWarnings = false;
+  bool hasLint = false;
   bool hasErrors = false;
 
   Map<String, Map<String, int>> whiteListMap
@@ -46,6 +47,7 @@ class CollectingDiagnosticHandler extends FormattingDiagnosticHandler {
 
   void checkResults() {
     Expect.isFalse(hasWarnings);
+    Expect.isFalse(hasLint);
     Expect.isFalse(hasErrors);
     Expect.isTrue(checkWhiteListUse());
     reportWhiteListUse();
@@ -102,6 +104,13 @@ class CollectingDiagnosticHandler extends FormattingDiagnosticHandler {
       }
       hasWarnings = true;
     }
+    if (kind == api.Diagnostic.LINT) {
+      if (checkWhiteList(uri, message)) {
+        // Suppress white listed warnings.
+        return;
+      }
+      hasLint = true;
+    }
     if (kind == api.Diagnostic.ERROR) {
       if (checkWhiteList(uri, message)) {
         // Suppress white listed warnings.