Revert "[d8] cleanly force exit in d8 on windows."

src/d8-posix.cc

Index: src/d8-posix.cc
diff --git a/src/d8-posix.cc b/src/d8-posix.cc
index cdfc39cc5de77e02880fc3bced34b13f811ab867..d2cf573d4c013207b62d0b35d4e68e89c24cb4bd 100644
--- a/src/d8-posix.cc
+++ b/src/d8-posix.cc
@@ -772,12 +772,4 @@ 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