DRILL-1098: Add test for trim(), substring() function.
Actual fix is in OPTIQ-331
DRILL-861: Implement sum, avg for decimal data type.
DRILL-1110: Output precision of functions should always be greater or equal to input precision
DRILL-730: Initialize the buffer while creating sparse representation from BigDecimal
DRILL-1109: Implement downward casting functions for decimal data type.
DRILL-743: New String Functions
DRILL-1088: implemented date_trunc use TestFunctionsQuery instead of TestDateFunctions
DRILL-1107: Fix regression from first patch