Remove one more lambda with closure for Nullable<T>

Also slightly optimize creating delegates for nullable delegates

Author: Sergio0694

src/WinRT.Runtime/ComWrappersSupport.cs

@@ -449,15 +449,26 @@ private static Func<IInspectable, object> CreateAbiNullableTFactory(
 #endif
             Type implementationType)
         {
+            // This method is only called when 'implementationType' has been validated to be some ABI.System.Nullable_Delegate<T>.
+            // As such, we know that the type definitely has a method with signature 'static Nullable GetValue(IInspectable)'.
             var getValueMethod = implementationType.GetMethod("GetValue", BindingFlags.Static | BindingFlags.NonPublic);
+
+#if NET6_0_OR_GREATER
+            return getValueMethod.CreateDelegate<Func<IInspectable, ABI.System.Nullable>>();
+#else
             return (IInspectable obj) => getValueMethod.Invoke(null, new[] { obj });
+#endif
         }
 
         private static Func<IInspectable, object> CreateArrayFactory(Type implementationType)
         {
-            var getValueFunc = (Func<IInspectable, object>)implementationType.GetHelperType().GetMethod("GetValue", BindingFlags.Static | BindingFlags.NonPublic).
-                CreateDelegate(typeof(Func<IInspectable, object>));
-            return getValueFunc;
+            var getValueMethod = implementationType.GetHelperType().GetMethod("GetValue", BindingFlags.Static | BindingFlags.NonPublic);
+
+#if NET6_0_OR_GREATER
+            return getValueMethod.CreateDelegate<Func<IInspectable, object>>();
+#else
+            return (Func<IInspectable, object>)getValueMethod.CreateDelegate(typeof(Func<IInspectable, object>));
+#endif
         }
 
         // This is used to hold the reference to the native value type object (IReference) until the actual value in it (boxed as an object) gets cleaned up by GC

src/WinRT.Runtime/TypeExtensions.cs

@@ -244,13 +244,10 @@ internal static Type GetAuthoringMetadataType(this Type type)
                     {
                         return null;
                     }
-                    else
 #endif
-                    {
-                        // Fallback code path for back compat with previously generated projections
-                        // running without AOT.
-                        return GetAuthoringMetadataTypeFallback(type);
-                    }
+                    // Fallback code path for back compat with previously generated projections
+                    // running without AOT.
+                    return GetAuthoringMetadataTypeFallback(type);
                 });
         }