Bug 16890: Make TestBuilder generate date for date columns (and not datetime)

Bug 16890: Make TestBuilder generate date for date columns (and not datetime)

TestBuilder should not generate datetime for date columns, but only for
datetime and timestamp columns.

Test plan:
Make sure the change in t/db_dependent/TestBuilder.t are consistent.
Before this patch, 1 of the 2 tests should fail.
After this patch applied, they both should pass.

Signed-off-by: Srdjan <srdjan@catalyst.net.nz>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>