[test] Calling the ctor of a class with a nested struct

This fails with

```
       Stack Trace:

          Child exception:
            System.BadImageFormatException: Could not resolve field token 0x04000014
          File name: 'System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType'
          /Users/alklig/work/dotnet-runtime/runtime/src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType/ReflectionAddNewType.cs(29,0):
          at
          System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType.ZExistingClass.ExistingMethod()

```

src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType/ReflectionAddNewType.cs

@@ -25,6 +25,8 @@ public class PreviousNestedClass {
         public event EventHandler<string> E;
         public void R() { E(this,"123"); }
     }
+
+    public static void ExistingMethod () {}
 }
 
 [AttributeUsage(AttributeTargets.All, AllowMultiple=true, Inherited=false)]

src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType/ReflectionAddNewType_v1.cs

@@ -38,6 +38,14 @@ public class NewNestedClass {};
     public static DateTime NewStaticField;
 
     public static double NewProp { get; set; }
+
+    public static void ExistingMethod ()
+    {
+        // modified
+        NewStaticField2 = new AnotherAddedClass();
+    }
+
+    public static AnotherAddedClass NewStaticField2;
 }
 
 [AttributeUsage(AttributeTargets.All, AllowMultiple=true, Inherited=false)]
@@ -87,3 +95,22 @@ public interface INewInterface : IExistingInterface {
 public enum NewEnum {
     Red, Yellow, Green
 }
+
+public class AnotherAddedClass
+{
+    public struct NewNestedStruct
+    {
+        public double D;
+        public object O;
+    }
+
+    public NewNestedStruct S;
+
+    public AnotherAddedClass()
+    {
+        S = new NewNestedStruct {
+            D = 1234.0,
+            O = "1234",
+        };
+    }
+}

src/libraries/System.Runtime.Loader/tests/ApplyUpdateTest.cs

@@ -625,6 +625,8 @@ public static void TestReflectionAddNewType()
                 var i = (System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType.IExistingInterface)o;
 
                 Assert.Equal("123", i.ItfMethod(123));
+
+                System.Reflection.Metadata.ApplyUpdate.Test.ReflectionAddNewType.ZExistingClass.ExistingMethod ();
             });
         }
     }