Fix breakage (TBR)

pkg/analyzer/lib/src/dart/ast/utilities.dart

Index: pkg/analyzer/lib/src/dart/ast/utilities.dart
diff --git a/pkg/analyzer/lib/src/dart/ast/utilities.dart b/pkg/analyzer/lib/src/dart/ast/utilities.dart
index e4e2008a10b701deb8c1a6bd49348310d161d9e2..8e45f3c37f9e160eb4c9e9848d129052ee55bfcf 100644
--- a/pkg/analyzer/lib/src/dart/ast/utilities.dart
+++ b/pkg/analyzer/lib/src/dart/ast/utilities.dart
@@ -8160,6 +8160,18 @@ class ToSourceVisitor2 implements AstVisitor<Object> {
   }
 
   @override
+  bool visitAssertInitializer(AssertInitializer node) {
+    sink.write("assert (");
+    safelyVisitNode(node.condition);
+    if (node.message != null) {
+      sink.write(', ');
+      safelyVisitNode(node.message);
+    }
+    sink.write(");");
+    return null;
+  }
+
+  @override
   Object visitAssertStatement(AssertStatement node) {
     sink.write("assert (");
     safelyVisitNode(node.condition);