src: dump isolate stats when process exits

When process exits, dump v8 isolate's internal stats for performance
evaluation and debugging.
It fixed the incorrect profiling log output when running V8's builtin
PGO profiling for node.js service type application,which exits by user
pressing CTRL+C etc. keys.

PR-URL: nodejs#44534
Reviewed-By: Anna Henningsen <[email protected]>

Author: qdaoming

src/api/environment.cc

@@ -766,6 +766,7 @@ ThreadId AllocateEnvironmentThreadId() {
 void DefaultProcessExitHandler(Environment* env, int exit_code) {
   env->set_can_call_into_js(false);
   env->stop_sub_worker_contexts();
+  env->isolate()->DumpAndResetStats();
   DisposePlatform();
   uv_library_shutdown();
   exit(exit_code);