tests: fix some mul_mat test gaps (#11375) Now that we have batched mat-vec mul Vulkan shaders for up to n==8, these tests weren't actually exercising the mat-mat mul path. Test n==9 as well. Also, change to use all_types.
tests: fix some mul_mat test gaps (#11375) Now that we have batched mat-vec mul Vulkan shaders for up to n==8, these tests weren't actually exercising the mat-mat mul path. Test n==9 as well. Also, change to use all_types.