Fix minimize step for method ref returning array (#79)

***UPDATE_DEPENDENTS***

Author: josesimoes

source/MetadataProcessor.Core/Tables/nanoSignaturesTable.cs

@@ -641,6 +641,10 @@ private void WriteSubTypeInfo(TypeReference typeDefinition, nanoBinaryWriter wri
             {
                 writer.WriteMetadataToken((uint)referenceId << 2);
             }
+            else
+            {
+                throw new ArgumentException($"Can't find entry in type reference table for {typeDefinition.FullName}.");
+            }
         }
     }
 }

source/MetadataProcessor.Core/nanoAssemblyBuilder.cs

@@ -369,7 +369,7 @@ private HashSet<MetadataToken> BuildDependencyList(MetadataToken token)
                                     mr.ReturnType.GetElementType().FullName != "System.Object" &&
                                     !mr.ReturnType.GetElementType().IsPrimitive)
                                 {
-                                    set.Add(mr.ReturnType.MetadataToken);
+                                    set.Add(mr.ReturnType.GetElementType().MetadataToken);
                                 }
                             }
                         }