Make OperatorExpression.refineValueType robust to cast expressions
Fix mispartitioned tuple error when INSERT contains non-trivial expression assigned to partitioning column
Let StatementPartitioning keep producing useful diagnostics in compiler report.
Make compiler report produce "explain" output for expressions instead of JSON.
Merge branch 'master' into ENG-5929-insert-cast-exception
Merge pull request #1701 from VoltDB/ENG-5929-insert-cast-exception

Allow non-trivial expressions assigned to partitioning column in `INSERT` statements.