DRILL-4682: Allow full schema identifier in SELECT clause

[vdiravka]

• changed SqlBracketlessSyntax logic in the DrillCompoundIdentifier;
• added checking of using full schema name in column names;
• added unit test testColumnNamesWithSchemaName;

[vdiravka]

@jinfengni Could you please review the changes

[jinfengni]

I feel it might be better to work on this issue after Drill rebases Calcite. I debugged a bit in SqlValidator, and seem that the code in Drill's forked Calcite is different from what Calcite master has. It's possible that some of patches (star column) in Drill's forked Calcite changes the behavior, and hence run into problem with the subquery cases. Since star column logic has been merged to Calcite master, it's better to try with this patch after rebasing on top of Calcite master, in stead of coming up with a temporary solution with restrictions.

[vdiravka]

@jinfengni Agree. It will be better to merge this patch after rebasing to the lastest version of calcite. Because currently I'm not sure how to solve this task in different manner than mine.

[ilooner]

@vdiravka Are you planning to complete this change?

[vdiravka]

@ilooner Yes, I am. It is in my backlog. The last status for it in my recent comment for DRILL-4682.