VxWorks doesn't have implementation of QStorageInfo and uses stub.
Remove tests of it from building and running, since these can't work.
Pick-to: 6.7
Task-number: QTBUG-115777
Change-Id: Idd63d20c2dda1ae09838a7d371ae5b713180cb96
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>