HIVE-25257: Incorrect row order validation for query-based MAJOR comp…

[kuczoram]

• Fix the row order validation for the query-based MAJOR compaction. The rows should be in increasing order by originalTransactionId, bucketProperty, rowId. But in the validation the bucketProperty is checked first, which can cause failure if there are delta directories with multiple statementIds, like after multiple merge statements.
• Added unit test for this use-case
• Fixed the error message printed out in the GenericUDFValidateAcidSortOrder by adding a toString() method to the WriteIdRowId inner class.