Fix a FP in explicit_counter_loop

[rail-rain]

Fixes #4677 and #6074

Fix a false positive in explicit_counter_loop where the loop counter is used after incremented, adjust the test so that counters are incremented at the end of the loop and add the test for this false positive.

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changelog: Fix a false positive in explicit_counter_loop where the loop counter is used after incremented

[rust-highfive]

r? @matthiaskrgr

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[matthiaskrgr]

Shouldn't we keep some tests where the counters are incremented at the start of the loop?

[rail-rain]

I've added an new one (theissue_4677 module) for it. I thought existing ones had different purposes; so, if I didn't move these println!, it would be doing two negative checks at the same time.

[matthiaskrgr]

Thanks!
@bors r+

[bors]

📌 Commit 5e393c7 has been approved by matthiaskrgr

[bors]

⌛ Testing commit 5e393c7 with merge 019c0d5...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: matthiaskrgr
Pushing 019c0d5 to master...