parallelization fix
XMerge remote-tracking branch 'upstream/master' into feature/parallelization_fix
Merge remote-tracking branch 'upstream/master' into feature/parallelization_fix
fixed tests
Adds total table size to print
TableScan and GenericExpressions are parallelizable now.
Added autojson tests for parallelized table scan.
Merge pull request #257 from kaihowl/pr/kh-tablescanpar

TableScan becomes ParallelizablePlanOperation.
Merge pull request #221 from JWUST/feature/parallelization_fix

Query Transformation Fix