AidlNode: delete copy constructor

So that it's easier to add invariants to these object's destructors.

Bug: 201584220
Test: aidl_unittests
Change-Id: Id152501cc8067743b73f52299588e3cd48b39144
diff --git a/aidl_unittest.cpp b/aidl_unittest.cpp
index fd64309..56faba5 100644
--- a/aidl_unittest.cpp
+++ b/aidl_unittest.cpp
@@ -1845,8 +1845,9 @@
   };
 
   auto set_nullable = [](std::unique_ptr<AidlTypeSpecifier>&& type) {
-    std::vector<AidlAnnotation> annotations;
-    annotations.emplace_back(*AidlAnnotation::Parse(AIDL_LOCATION_HERE, "nullable", {}, {}));
+    std::vector<std::unique_ptr<AidlAnnotation>> annotations;
+    annotations.emplace_back(std::unique_ptr<AidlAnnotation>(
+        AidlAnnotation::Parse(AIDL_LOCATION_HERE, "nullable", {}, {})));
     type->Annotate(std::move(annotations));
     return std::move(type);
   };