解析状态变量的 path
stores.foo.bar => { storeName: 'foo', variableName: 'bar' } Copy
stores.foo.bar => { storeName: 'foo', variableName: 'bar' }
stores.user.count => { storeName: 'user', variableName: 'count' } Copy
stores.user.count => { storeName: 'user', variableName: 'count' }
解析状态变量的 path