Fix tests including dead_code warnings

[TaKO8Ki]

This patch is related to rust-lang/rust#97853. In it, I made some changes to collapse multiple dead code warnings into a single diagnostic. They broke some tests in cargo. After rust-lang/rust#97853 is merged, this PR should be merged.

[rust-highfive]

r? @ehuss

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[TaKO8Ki]

rust-lang/rust#97853 was merged. After a nightly including it is released, this PR should be merged.

[ehuss]

Thanks! As mentioned in rust-lang/rust#97853 (comment), when there are diagnostic changes that interfere with cargo's testsuite, the preferred route is to change the test to work with either version of rustc, merge that to master, and then update the submodule.

For example, these tests could have been modified to something like [WARNING] [..]`dead`[..] which would work with either version.

I'll go ahead and merge this to fix CI. If these kinds of changes come up in the future, we can further adjust these tests to be more general. Cargo doesn't really care about the specific error/warning text, just that something appears.

@bors r+

[bors]

📌 Commit 03a8490 has been approved by ehuss

[bors]

⌛ Testing commit 03a8490 with merge 9e2062085df7582da853afaa0ffa050710ac60fb...

[bors]

💔 Test failed - checks-actions

[ehuss]

I posted #10785 with the fixes to work on both stable and nightly. I'm going to go ahead and close this in favor of that.