Integration tests for Precision in Lite

[awaelchli]

What does this PR do?

Converts the precision plugin integration tests from PL to Lite tests where applicable.
The tests can be classified into three groups (annotated in code for review):

• adopted: This test was fully or partially adopted into Lite
• skipped: The test is legacy or questionable whether it is of any use at all
• unimplemented: This test covers functionality only available in Trainer, and can't be ported to Lite. Example: Apex

Before submitting

• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes? (if necessary)
• Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you update the CHANGELOG? (not for typos, docs, test updates, or internal minor changes/refactorings)

PR review

Anyone in the community is free to review the PR once the tests have passed.
Before you start reviewing make sure you have read Review guidelines. In short, see the following bullet-list:

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
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Did you have fun?

I made sure I had fun coding 🙃

cc @carmocca @justusschock @awaelchli @Borda @akihironitta @rohitgr7