Many tests intentionally trigger errors. A debug-only log setting sent those errors to stdout. The resulting stack dumps simply cluttered the test output, so disabled error output to the console.
Drill can apply bounds checks to vectors. Tests run via Maven enable bounds checking. Now, bounds checking is also enabled in "debug mode" (when assertions are enabled, as in an IDE.)
Drill contains two test frameworks. The older BaseTestQuery was marked as deprecated, but many tests still use it and are unlikely to be changed soon. So, removed the deprecated marker to reduce the number of spurious warnings.