Spurious warnings about inapplicable hints.

With CBO on, during join enumeration, the same hint may be applicable during one join order, and may be inapplicable during a different join order. Since we generate the warning as soon as we encounter it, if it becomes applicable in a different join order, the warning should be suppressed.

select 017, count(1)  from  S   join T on S.u1K  /*+ hashjoin build (T) */ = T.u1K join U on T.u4K   = U.u4K;

select 017, count(1)  from  S   join T on S.u1K  /*+ hashjoin build (T) */ = T.u1K join U on T.u4K  /*+ hashjoin build (S) */ = U.u4K;