Removed memory leaks caused by specifiers for bases.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Core/Parser/ASTConverter.cs

@@ -713,6 +713,8 @@ namespace CppSharp
                 Offset = @base.Offset
             };
 
+            NativeObjects.Add(@base);
+
             return _base;
         }