Disable experimental natives when creating a start-up snapshot.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index eb2269c15ecf6292d86e553157b532a33d5894ab..960406d59ad6726b3bb4f3f4cc0dea541d8b1d6f 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2891,9 +2891,13 @@ Genesis::Genesis(Isolate* isolate,
     isolate->counters()->contexts_created_from_scratch()->Increment();
   }
 
-  // Install experimental natives.
-  if (!InstallExperimentalNatives()) return;
-  InitializeExperimentalGlobal();
+  // Install experimental natives. Do not include them into the snapshot as we
+  // should be able to turn them off at runtime. Re-installing them after
+  // they have already been deserialized would also fail.
+  if (!isolate->serializer_enabled()) {
+    if (!InstallExperimentalNatives()) return;
+    InitializeExperimentalGlobal();
+  }
 
   // The serializer cannot serialize typed arrays. Reset those typed arrays
   // for each new context.