Fixes torch jit tracing for LayoutLMv2 model (re-open)
Author: mikkeldenker
Pull request: yes

# What does this PR do?

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This PR re-opens #14462 with the current changes in master merged into the branch. Please see the original PR for more details.



## Before submitting
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## Who can review?

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@LysandreJik
@NielsRogge

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Comments:
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