Code cleanup in check_match.rs

[jfirebaugh]

Best reviewed ignoring whitespace changes.

See commits for individual changes.

Based on the commit comment for 5af5f26, I believe the exports were used by old trans and became unused with #35764.

[rust-highfive]

r? @Aatch

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[jfirebaugh]

Pinging @arielb1 per @eddyb on IRC -- I understand if there's a reluctance for pure "cleanup" PRs due to the potential for causing merge conflicts.

[eddyb]

The conflict in question is with #36695 - if you two can agree on a way to handle this, it'd be great.

[jfirebaugh]

Thanks for the pointer @eddyb. @arielb1, I'm happy to wait for #36695 to land -- some or all of these changes may well be unnecessary after that. Let me know.

[bors]

☔ The latest upstream changes (presumably #36695) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

Closing due to inactivity, but feel free to resubmit with a rebase!