This continues the work on dot product instructions already started in 3cdac06. This change adds support for all OpenCL integer dot product builtins under `cl_khr_integer_dot_product` extension, namely: ``` * dot * dot_acc_sat * dot_4x8packed_(uu/ss/su/us)_(u)int * dot_acc_sat_4x8packed_(uu/ss/su/us)_(u)int ```