Unload debugger on isolate deinit.

R=hpayer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/18682003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15521 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/isolate.cc

@@ -1877,6 +1877,10 @@ void Isolate::Deinit() {
   if (state_ == INITIALIZED) {
     TRACE_ISOLATE(deinit);
 
+#ifdef ENABLE_DEBUGGER_SUPPORT
+    debugger()->UnloadDebugger();
+#endif
+
     if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Stop();
 
     if (FLAG_sweeper_threads > 0) {