- Use std::uint64_t instead of size_t to avoid implementation-defined type.
- Rename to bst_idx_t, to account for other types of indexing.
- Small cleanup to the base header.
Thrust implementation of `thrust::all_of/any_of/none_of` adopts an early stopping strategy
to bailout early by dividing the input into small batches. This is not ideal for data
validation as we expect all data to be valid. The strategy leads to excessive kernel
launches and stream synchronization.
* Use reduce from dh instead.
