inductor: align cpp floordiv with python floordiv for dyanmic shape path (#102068)
This PR does the following things:
- Align the C++ behavior with Python for FloorDiv.
- Always return expr dtype for some ops which not use expr's dtype to do the computation.
After this PR, TIMM ```levit_128``` and ```volo_d1_224``` accuracy tests can be passed for dynamic shape path.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102068
Approved by: https://github.com/jgong5, https://github.com/ngimel
