[d8] cleanly force exit in d8 on windows.

Using _exit on windows may cause race conditions in threads.

BUG=chromium:603131

Review-Url: https://codereview.chromium.org/2478473003
Cr-Commit-Position: refs/heads/master@{#40789}

src/d8-posix.cc

@@ -772,4 +772,12 @@ void Shell::AddOSMethods(Isolate* isolate, Local<ObjectTemplate> os_templ) {
                 FunctionTemplate::New(isolate, RemoveDirectory));
 }
 
+void Shell::Exit(int exit_code) {
+  // Use _exit instead of exit to avoid races between isolate
+  // threads and static destructors.
+  fflush(stdout);
+  fflush(stderr);
+  _exit(exit_code);
+}
+
 }  // namespace v8

src/d8-windows.cc

@@ -10,5 +10,12 @@ namespace v8 {
 
 void Shell::AddOSMethods(Isolate* isolate, Local<ObjectTemplate> os_templ) {}
 
+void Shell::Exit(int exit_code) {
+  // Use TerminateProcess avoid races between isolate threads and
+  // static destructors.
+  fflush(stdout);
+  fflush(stderr);
+  TerminateProcess(GetCurrentProcess(), exit_code);
+}
 
 }  // namespace v8

src/d8.cc

@@ -1569,16 +1569,6 @@ Local<Context> Shell::CreateEvaluationContext(Isolate* isolate) {
   return handle_scope.Escape(context);
 }
 
-
-void Shell::Exit(int exit_code) {
-  // Use _exit instead of exit to avoid races between isolate
-  // threads and static destructors.
-  fflush(stdout);
-  fflush(stderr);
-  _exit(exit_code);
-}
-
-
 struct CounterAndKey {
   Counter* counter;
   const char* key;