vinyl: don't use vy_stmt_new_surrogate_delete if not necessary

There are three places where we use this expensive functions while we
could get along with a cheaper one:

 - Deferred DELETE space on_replace trigger. Here we can use simple
   vy_stmt_new_delete, because the trigger is already passed a surrogate
   DELETE statement.

 - Secondary index build on_replace trigger. Here we can extract the
   secondary key, set its type to DELETE and insert it into the index.
   We don't need all the other indexed fields.

 - Secondary index build recovery procedure. Similarly to the previous
   case, we can use extracted here rather than building a surrogate
   DELETE statement.