DRILL-3993: Changes after review:
Moved checks for OOM into spillIfNeeded method to avoid excessive call of chooseAPartitionToFlush method.
Ignored unit tests until DRILL-6018 is fixed.
These failures appears because new Calcite tries to simplify expressions from the query when applying ReduceExpressionsRule and fails with NFE.
Similar problem, but with old version of Calcite was described in DRILL-6018, therefore these unit tests are marked as ignored until DRILL-6018 is fixed.
