host.Start()启动后的host对象和从容器获取的IWorkflowHost对象不一样

**Describe the bug**
host.Start()启动后的host对象和从容器获取的IWorkflowHost对象不一样，从容器获取的IWorkflowHost对象无法启动工作流，提示工作流未注册。

`
//启动代码片段
var host = provider.GetService();
host.RegisterWorkflow();
host.Start();

CommonUtitl.workflowHost = host; //保存对象全局使用
`

`
string id = "TestWorkflow";
int version = 1;
string workflowId = null;
var def = _registry.GetDefinition(id, version); //结果：null
var def2 = CommonUtitl.workflowHost.Registry.GetDefinition(id, version); //结果：有值
var tt = CommonUtitl.workflowHost == _workflowHost; //结果：不相等
`

**To Reproduce**

**Expected behavior**
从容器获取的IWorkflowHost对象和host.Start();后一样

**Additional context**
Add any other context about the problem here.