Make constant map literal ordered.

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 efb81e35920907b7e795f58800178ee431f27608..1f5635ca66e684e42499041f47562833a39d40e9 100644
--- a/pkg/analyzer/lib/src/generated/constant.dart
+++ b/pkg/analyzer/lib/src/generated/constant.dart
@@ -1799,8 +1799,8 @@ class ConstantVisitor extends UnifyingAstVisitor<DartObjectImpl> {
       return null;
     }
     bool errorOccurred = false;
-    HashMap<DartObjectImpl, DartObjectImpl> map =
-        new HashMap<DartObjectImpl, DartObjectImpl>();
+    LinkedHashMap<DartObjectImpl, DartObjectImpl> map =
+        new LinkedHashMap<DartObjectImpl, DartObjectImpl>();
     for (MapLiteralEntry entry in node.entries) {
       DartObjectImpl keyResult = entry.key.accept(this);
       DartObjectImpl valueResult = entry.value.accept(this);