2) Slightly refactored the looper call chain to avoid code duplication.
3) Fixed CORE-4010: Fetch cannot be subsequently interrupted via DELETE FROM MON$STATEMENTS.
Also some cleanups, the most important are:
- meaningful ctor on Jrd::Lock, helping to avoid code dup
- avoid unneeded h-file dependencies, making boot build engine dependent
- Changed streams from UCHAR to ULONG as Dmitry wanted
- Got rid of some redundant flags to indicate BLR level
- Misc changes (for example, converted to test for DBB_read_only in Database to a function)
- BLR v6 is left commented (waiting for a better solution to appear, if any exists)
- This change is not going to raise the engine limits until a solution is found to express more than 255 streams in BLR.
2. Avoid massive segfaults when closing heavily loaded server.
3. Restored logic in YValve required for correct shutdown.
4. Do not change externally visible request body when preparing it.
Refactored the shared counter to support multiple number spaces.
Changed att_id and tra_id to be generated sequentially (without caching), as agreed with Vlad privately.
Fixed CORE-2305: Make mon$statement_id value constant among monitoring snapshots.
Store ValueExprNodes instead of jrd_nod in the metadata cache.
Make RecordSourceNode child of ExprNode as they share most operations.
Get rid of the JRD visitors in favor of direct calls.
Convert assignments statement lists created inside expressions to separate source and targets ValuesExprNodes.
2) Created ExprNode::expressionEqual method to replace a new big and ugly switch.
3) Make boolean referencers use BoolExprNode instead of jrd_nod, except nod_validate for now. This includes BinaryBoolNode and NotBoolNode working without jrd_nod references.
4) Rework in the impure allocation code (replace "csb_impure += ..." by CMP_impure calls).
