Singleton initalization type is not properly rewritten

```
public class SingletonTest
{
private static SingletonTest _instance;

public static SingletonTest Instance
{
get
{
if (_instance == null)
{
_instance = new SingletonTest(); //Won't be rewritten to __Patched_ version, even with AllPatchedIdentifiersRewriter enabled
}
return _instance;
}
}

private SingletonTest()
{

}
}
```

Start by reproducing the SingletonTest example with AllPatchedIdentifiersRewriter enabled and trace the rewriting path for the new SingletonTest() expression. Done means the singleton initialization is rewritten to the __Patched_ version as described in the issue.

索引モデルが issue の本文から書いたものです。