P4
GCDrainStackTargetSize is defined as `uintx`, but all use sites expect/need `uint`.
Another constraint is from `_stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1)`, where the field is `uint`. Therefore, the actual valid range is `[0, (max_juint - 1)/2]`.
Another constraint is from `_stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1)`, where the field is `uint`. Therefore, the actual valid range is `[0, (max_juint - 1)/2]`.
