Reload native extensions when starting from a snapshot.

runtime/bin/main.cc

Index: runtime/bin/main.cc
diff --git a/runtime/bin/main.cc b/runtime/bin/main.cc
index bd1e6affac4230458b7aebe253dcf0a84543837f..b481a67980e4721ed264860c35b2811757340efb 100644
--- a/runtime/bin/main.cc
+++ b/runtime/bin/main.cc
@@ -815,6 +815,10 @@ static Dart_Isolate CreateIsolateAndSetupHelper(const char* script_uri,
     Builtin::SetNativeResolver(Builtin::kBuiltinLibrary);
     Builtin::SetNativeResolver(Builtin::kIOLibrary);
   }
+  if (run_app_snapshot) {
+    Dart_Handle result = Loader::ReloadNativeExtensions();
+    CHECK_RESULT(result);
+  }
 
   // Set up the library tag handler for this isolate.
   Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);