Exchanging operands of a comparision operator should invert the operator.

pkg/analysis_server/test/mock_sdk.dart

Index: pkg/analysis_server/test/mock_sdk.dart
diff --git a/pkg/analysis_server/test/mock_sdk.dart b/pkg/analysis_server/test/mock_sdk.dart
index c539226896240e4ffb004b3495acd1b6e9cbd61c..ffca2a3422bcae323538d1f57c3237d092d4d466 100644
--- a/pkg/analysis_server/test/mock_sdk.dart
+++ b/pkg/analysis_server/test/mock_sdk.dart
@@ -40,6 +40,9 @@ class String implements Comparable<String> {
 class bool extends Object {}
 abstract class num implements Comparable<num> {
   bool operator <(num other);
+  bool operator <=(num other);
+  bool operator >(num other);
+  bool operator >=(num other);
   num operator +(num other);
   num operator -(num other);
   num operator *(num other);