Investigate later hint resolution

Investigate resolving hints later to solve chicken/egg problem where hints are needed for derived tables before all VIEWs are opened. The basic premise is that we open VIEWs (which are treated as derived tables) after lexing the parent select. This select and its query blocks are numbered. It may specify hints that have an effect within VIEWs (like [NO_]MERGE) but we won't know until after we open VIEWs. So we need to reconsider derived merge hints again after opening VIEWs. (In effect, we make a decision regarding the hint treatment during parent query lexing, and then have to revisit it upon opening a VIEW, or at the very least defer such decisions until after we open VIEWs).

From Slack:

Parsing

  open tables

    LOC1: (somewhere inside we check for OPTIMIZER_SWITCH_DERIVED_MERGE  and hint with the same meainig) (edited) 

      > here we learn that some tables are views and that they have child select #N , #N+1, #N+2 ...

Name resolution

  somewhere here we check for DERIVED_MERGE again (?)

  Maybe here we could "reconsider" the decision made at LOC1

Defer resolution until

  JOIN object construction ?

  fix_fields for items ?