Describe the bug
Currently, in the case that a random transform contains another random transform, we have 2 different ways to set the random status:

1. Use the self.R of first transform the second:
   https://github.com/Project-MONAI/MONAI/blob/dev/monai/transforms/croppad/dictionary.py#L761
2. Use the same random seed or state for both transforms:
   https://github.com/Project-MONAI/MONAI/blob/dev/monai/transforms/intensity/dictionary.py#L177

@wyli @rijobro @ericspod Which one do you guys think is better? Then I can try to unify them.