Fix dot*w to return 0 for empty vectors (BLAS interface)
Fix dot*w to return 0 for empty vectors (BLAS interface)

ROCmSoftwarePlatform/hipeigen,toastedcrumpets/eigen,TSC21/Eigen,pasuka/eigen,Zefz/eigen,TSC21/Eigen,ritsu1228/eigen,ritsu1228/eigen,toastedcrumpets/eigen,ROCmSoftwarePlatform/hipeigen,ROCmSoftwarePlatform/hipeigen,TSC21/Eigen,Zefz/eigen,Zefz/eigen,pasuka/eigen,ritsu1228/eigen,TSC21/Eigen,ritsu1228/eigen,toastedcrumpets/eigen,toastedcrumpets/eigen,pasuka/eigen,ROCmSoftwarePlatform/hipeigen,ritsu1228/eigen,pasuka/eigen,Zefz/eigen,pasuka/eigen