Serialize and resynthesize unresolved constant instance creations.

pkg/analyzer/lib/src/summary/prelink.dart

Index: pkg/analyzer/lib/src/summary/prelink.dart
diff --git a/pkg/analyzer/lib/src/summary/prelink.dart b/pkg/analyzer/lib/src/summary/prelink.dart
index cecc936bd2eaa311448793266b971b5c37bb337a..688abe542db361e5e5b4de21218071110f25ce9f 100644
--- a/pkg/analyzer/lib/src/summary/prelink.dart
+++ b/pkg/analyzer/lib/src/summary/prelink.dart
@@ -423,6 +423,11 @@ class _Prelinker {
             continue;
           }
         }
+        // Anything prefixed with 'unresolved' is unresolved.
+        if (references[reference.prefixReference].kind ==
+            ReferenceKind.unresolved) {
+          namespace = const <String, _Meaning>{};
+        }
         // Prefix references must always point to proper prefixes.
         assert(namespace != null);
       }