[Matrix]: fix a minor bug in block MV test.
[Matrix]: fix a minor bug in block MV test.

flashxio/FlashX,icoming/FlashGraph,icoming/FlashX,icoming/FlashX,flashxio/FlashX,icoming/FlashGraph,flashxio/FlashX,zheng-da/FlashX,flashxio/FlashX,icoming/FlashGraph,icoming/FlashGraph,zheng-da/FlashX,flashxio/FlashX,zheng-da/FlashX,icoming/FlashGraph,icoming/FlashX,zheng-da/FlashX,zheng-da/FlashX,icoming/FlashX,icoming/FlashX,flashxio/FlashX