src,worker: runtime error on pthread creation

with large number of worker threads pthread
fails with hard assertion.
Instead of hard assertion throw a runtime error.

Refs: nodejs#32319

src/node_worker.cc

@@ -623,7 +623,7 @@ void Worker::StartThread(const FunctionCallbackInfo<Value>& args) {
   uv_thread_options_t thread_options;
   thread_options.flags = UV_THREAD_HAS_STACK_SIZE;
   thread_options.stack_size = kStackSize;
-  CHECK_EQ(uv_thread_create_ex(&w->tid_, &thread_options, [](void* arg) {
+  int ret = uv_thread_create_ex(&w->tid_, &thread_options, [](void* arg) {
     // XXX: This could become a std::unique_ptr, but that makes at least
     // gcc 6.3 detect undefined behaviour when there shouldn't be any.
     // gcc 7+ handles this well.
@@ -644,7 +644,37 @@ void Worker::StartThread(const FunctionCallbackInfo<Value>& args) {
           w->JoinThread();
           // implicitly delete w
         });
-  }, static_cast<void*>(w)), 0);
+  }, static_cast<void*>(w));
+  if (ret != 0) {
+    char err_buf[128];
+    uv_err_name_r(ret, err_buf, sizeof(err_buf));
+    w->custom_error_ = "ERR_WORKER_INIT_FAILED";
+    w->custom_error_str_ = err_buf;
+    w->loop_init_failed_ = true;
+    w->thread_joined_ = true;
+    w->stopped_ = true;
+    w->env()->remove_sub_worker_context(w);
+    {
+      HandleScope handle_scope(w->env()->isolate());
+      Context::Scope context_scope(w->env()->context());
+      // Reset the parent port as we're closing it now anyway.
+      w->object()->Set(w->env()->context(),
+                    w->env()->message_port_string(),
+                    Undefined(w->env()->isolate())).Check();
+      Local<Value> args[] = {
+          Integer::New(w->env()->isolate(), w->exit_code_),
+          w->custom_error_ != nullptr
+              ? OneByteString(w->env()->isolate(), w->custom_error_).As<Value>()
+              : Null(w->env()->isolate()).As<Value>(),
+          !w->custom_error_str_.empty()
+              ? OneByteString(w->env()->isolate(), w->custom_error_str_.c_str())
+                    .As<Value>()
+              : Null(w->env()->isolate()).As<Value>(),
+      };
+      w->MakeCallback(w->env()->onexit_string(), arraysize(args), args);
+    }
+  w->MakeWeak();
+  }
 }
 
 void Worker::StopThread(const FunctionCallbackInfo<Value>& args) {