Fix tensor getitem bug (#5474)

* printf tensor index in cpp

* revert printf debug information

* add isinstance tuple and int condition

* format code

* implement and register __iter__ method

* Change to catch exception from C++ and throw IndexError

* add indexError error message

Co-authored-by: oneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>