Remove JH generate test file

What does this MR do and why?

Remove generate test file feature adaption in JH.

The updates from Upstream have broken JH's testing. Related failed job: https://jihulab.com/gitlab-cn/gitlab/-/jobs/12401897

JH currently has no plans to continue maintaining generate test file feature in the short term, so the feature is being removed from JH's adaptation.

CC @yzzou

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