Fix some `TFWhisperModelIntegrationTests`
# What does this PR do?

(Probably since the introduction of `GenerationConfig`), some TF Whisper Integration tests fail with error 

```bash
ValueError: The following `model_kwargs` are not used by the model: ['language', 'task'] (note: typos in the generate arguments will also show up in this list)
```

From my understanding, we should pass some arguments via `generation_kwargs`.

Note that `WhisperForConditionalGeneartion` has its custom `generate` but `TFWhisperForConditionalGeneartion` doesn't.

⚠️ When I try to apply the same changes to PyTorch Whisper test methods, it fails as the output is different.

We are somehow in a trouble of the inconsistency between PT/TF.

(Not sure if we should overwrite `generate` in `TFWhisperForConditionalGeneartion`.)
_The documentation is not available anymore as the PR was closed or merged._<|||||>> LGTM- thanks for fixing!
> 
> Regarding the PyTorch tests failing with the same inputs - how do they fail?

It gives different outputs <|||||>I am very sorry, **I was doing something stupid and made wrong claims**. The `generation_kwargs` is an argument to the `__init__` of `GenerationConfig` instead of the `generate` method. 

(Some of) The previous failing tests pass as the 2 problematic arguments to `generate` are not passed, but this is wrong logic.

**I will look in more depth.**<|||||>Well, I finally decided  to overwrite `generate` for `TFWhisperForConditionalGeneartion`.