Use non-public methods too

Author: SergeiPavlov

Orm/Xtensive.Orm/Orm/Linq/MemberCompilation/MemberCompilerProvider.cs

@@ -184,7 +184,7 @@ private static (MemberInfo targetMember, Delegate compilerInvoker) ProcessCompil
             Strings.ExCompilerXHasInvalidTargetType, compiler.GetFullName(true)));
 
       var parameterTypes = ValidateCompilerParametersAndExtractTargetSignature(compiler, isGeneric);
-      var bindingFlags = BindingFlags.Public;
+      var bindingFlags = BindingFlags.Public | BindingFlags.NonPublic;
 
       if (isCtor)
         bindingFlags |= BindingFlags.Instance;