Linker cannot determine whether suppression is redundant if the method body is unreachable.

Consider the following code:
```csharp
public static void Test ()
{
UsedToMarkMethod (null);
}

static void UsedToMarkMethod (Type t)
{
t.MethodConvertedToThrow ();
}

class Type
{
[UnconditionalSuppressMessage ("Test", "IL2072")]
public string MethodConvertedToThrow ()
{
// Trigger IL2072 warning
}
}
```
The body of `MethodConvertedToThrow ()` is unreachable and will not be processed. The linker is unable to determine whether the suppression on this method is useful.