[CI] Don't test apex

[sshleifer]

No description provided.

[codecov]

Codecov Report

Merging #6021 into master will increase coverage by 0.39%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #6021      +/-   ##
==========================================
+ Coverage   78.29%   78.68%   +0.39%     
==========================================
  Files         146      146              
  Lines       26249    26249              
==========================================
+ Hits        20552    20655     +103     
+ Misses       5697     5594     -103     

Impacted Files	Coverage Δ
src/transformers/modeling_tf_roberta.py	43.98% <0.00%> (-49.38%)	⬇️
src/transformers/generation_tf_utils.py	86.21% <0.00%> (ø)
src/transformers/modeling_openai.py	82.25% <0.00%> (+1.29%)	⬆️
src/transformers/modeling_tf_openai.py	95.18% <0.00%> (+74.91%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3996041...14292a2. Read the comment docs.