SH query execution migrated from SH::init() into create_SH().
There is a session variable columnstore_processing_handlers_fallback
that allows to fallback to DH, GBH if SH fails. DH now uses semantic
tree check for unsupported features to allow to fallback to GBH or
storage API.
Fixes GBH related bug when create_GBH() returns a handler for
queries with impossible WHERE/HAVING.
Fixed bug in FromSubquery::transform() where isUnion is set to true.
Enabled RTTI b/c server team enabled it for MDB.
Removed unused code supposed to be used with vtable.
Used Item attribute getters introduced by 10.4
Make changes to support Item::CONST_ITEM introduced by 10.4
as a replacement for INT_,REAL_,STRING_ ITEM.
Replaced QT_INFINIDB_DERIVED and similar flags
with correponded flags for Item->print().
Replaced or commented out infinidb_ variable names with columnstore_
where applicable.
SELECT_LEX had been moved in THD so changed all references.
Avoid writing CS decimal scales into MDB decimal fields
d-only dec attribute. WIP
Replaced infinidb_vtable with a singleton MIGR.
Merged with MCOL-2121.
Added new wsrep include paths needed by UDaF code.
Removed .vcxproj from Connector code.
Renamed isInfiniDB() into isMCSTable
Changed getSelectPlan() to reuse it with derived and
other handler types.
Separate pushdown handlers methods and functions.
Removed vcxproj files from the source.
Added fix for MCOL-2166.
Merged with MCOL-2121
