DRILL-7007: Use verify method in row set tests
Many of the early RowSet-based tests used the pattern:
new RowSetComparison(expected)
.verifyAndClearAll(result);
Revise this to use the simplified form:
RowSetUtilities.verify(expected, result);
The original form is retained when tests use additional functionality, such as the ability to perform multiple verifications on the same expected batch.
closes #1624
