reorg of test scripts and minor changes to tests

[pacman100]

What does this PR do?

1. Reorg test scripts with external dependencies such as datasets, transformers ...
2. lower performance threshold from 0.83 to 0.82 as it leads to assertion error on GCP instance with 2 T4 GPUs which run in CI slow test.
3. Adding fix to deepspeed as per [BUG] Error when enabling fp16 config with tasks involving FloatTensor Inputs such as Image Classification, Speech Recognition ... deepspeedai/DeepSpeed#2019

All slow tests are now passing on GCP instance with 2 T4 GPUs
report_fsdp.txt
report_deepspeed_mem_test.txt
report_deepspeed_checkpoint_test.txt
report_deepspeed_performance_test.txt

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[sgugger]

LGTM, thanks for working on this!
(Let's wait for @muellerzr before merging though)

[muellerzr]

Thanks for this!

As discussed offline this likely won't affect our slow multi-gpu runner that is failing, as that seems to be a different issue entirely.