feat(imperative): add advance indexing with bool

also fix bug to deal with empty tensor in np2tensor

GitOrigin-RevId: 2bd8152c90

dnn/src/cuda/cond_take/opr_impl.cpp

@@ -82,6 +82,7 @@ CondTakeImpl::Output CondTakeImpl::exec(
             break; \
         }
         MEGDNN_FOREACH_COMPUTING_DTYPE(cb)
+        cb(::megdnn::dtype::Bool)
 #undef cb
         default:
             megdnn_throw("bad data dtype");