Fix CI: regenerate known-good outputs with latest Rust nightly

[adamgreig]

This was a little boring! There aren't any serious changes except to the exceptions app which has changed around a bit; I haven't thoroughly checked the new assembly but don't have any reason to think it's wrong, just the result of much newer LLVM/Rust.

[rust-highfive]

r? @therealprof

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[adamgreig]

Ah, cool, the objdump format has changed between our 1.51 and stable/nightly. I haven't bisected the exact version where it changed; bumping MSRV to 1.58.

[bors[bot]]

Timed out.

[eldruin]

Ah, the bors config needs to be updated due to the MSRV change.

[adamgreig]

Oops, thanks. Updated.

[bors[bot]]

Build succeeded:

• build (1.58.1)
• build (stable)