Since 7a42c8c1

 QTestTablePrivate no
longer cleans up the memory it holds in dataList. This will make tools
such as valgrind/address-sanitizer generate a lot of noise about
directly or indirectly leaked memory.

Change-Id: Ic0900ecdd7b76cda9f5366f3950bccde2f1b244c
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>