Fix a number of issues with divs in ValueRangeAnalysis (#100547)
This PR:
- Adds `floordiv` and `truncdiv` as they were missing
- Maps `div` to its correct definition (it was being mapped to `floordiv`)
- Simplifies the bounds of `floordiv`
- Fixes some issues with the returned types of `floor` `ceil`
- Adds tests for the previous point
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100547
Approved by: https://github.com/ezyang
