Correctly initialize message handler for --cache=code

R=machenbach@chromium.org

Change-Id: I59a373d838678ec8659a3014e5e3184e5c2d5c12
Reviewed-on: https://chromium-review.googlesource.com/1209462Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55684}

src/d8.cc

@@ -3504,6 +3504,7 @@ int Shell::Main(int argc, char* argv[]) {
           Shell::HostInitializeImportMetaObject);
       {
         D8Console console(isolate2);
+        Initialize(isolate2);
         debug::SetConsoleDelegate(isolate2, &console);
         PerIsolateData data(isolate2);
         Isolate::Scope isolate_scope(isolate2);