Update expected values in CodeGen tests
# What does this PR do?

Update expected values in CodeGen test `test_codegen_sample`. The currently value works for other GPU, but for Nvidia T4, we need the values in this PR. 

Note that `do_sample` will call `self.sample` (in `generatioin_utils.py`) which uses `torch.multinomial`, which is not 100% reproducible across different accelerators.
_The documentation is not available anymore as the PR was closed or merged._<|||||>kindly ping @patil-suraj as I am eager toward 0 test failure 🚀 on CI report 