Fix the snapshotter to generate valid precompilation snapshots

runtime/bin/gen_snapshot.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ skipping 417 matching lines @@
   Dart_Handle script_path = FilePathFromUri(
       DartUtils::GetStringValue(resolved_script_uri));
   if (Dart_IsError(script_path)) {
     return script_path;
   }
   Dart_Handle source = DartUtils::ReadStringFromFile(
       DartUtils::GetStringValue(script_path));
   if (Dart_IsError(source)) {
     return source;
   }
-  return Dart_LoadLibrary(resolved_script_uri, source, 0, 0);
+  if (IsSnapshottingForPrecompilation()) {
+    return Dart_LoadScript(resolved_script_uri, source, 0, 0);
+  } else {
+    return Dart_LoadLibrary(resolved_script_uri, source, 0, 0);
+  }
 }
 
 
 static Dart_Handle LoadGenericSnapshotCreationScript(
     Builtin::BuiltinLibraryId id) {
   Dart_Handle source = Builtin::Source(id);
   if (Dart_IsError(source)) {
     return source;  // source contains the error string.
   }
   Dart_Handle lib;
@@ skipping 688 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }