Add missing tests for 'E-needstest' labeled issues

[topecongiro]

This PR adds missing tests for issue #35988, #19712, #18627, #24947, #28600 and #34751.

Fixes #35988
Fixes #19712
Fixes #24947
Fixes #28600
Fixes #34751

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

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[petrochenkov]

@topecongiro
Could you remove the test for #18627? It's not actually fixed.

[topecongiro]

Removed the test for #18627 & rebased.

[petrochenkov]

@bors r+

[bors]

📌 Commit a54f9dd has been approved by petrochenkov

[bors]

⌛ Testing commit a54f9dd with merge 11bc48a...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: petrochenkov
Pushing 11bc48a to master...

[brson]

Awesome PR @topecongiro 👍