[ASTERIXDB-1753][SQL] Disable auto-plural for group-by. - user model changes: do not perform auto-scalar-to-plural transition for variables that are defined prior to a group-by group clause after the group-by clause. - storage format changes: no - interface changes: no
details: - migrated existing test queries that use auto-plural; - added a negative test query.
Use backticks instead of double quotes for delimited identifiers in SQL++. Change-Id: I2db58d68e8e28befa4105504c261b101fa0285af Reviewed-on: https://asterix-gerrit.ics.uci.edu/909 Reviewed-by: Jenkins <firstname.lastname@example.org> Tested-by: Jenkins <email@example.com> Reviewed-by: Till Westmann <firstname.lastname@example.org>