clippy(uptime): fix some lints on windows

[xtqqczze]

Fix some lints (even though uptime fails to build on Windows).

Related: #7256

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tty/tty-eof (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/tail/tail-n0f is now being skipped but was previously passing.
Congrats! The gnu test tests/cp/link-heap is now passing!
Congrats! The gnu test tests/dd/no-allocate is now passing!
Congrats! The gnu test tests/seq/seq-epipe is now passing!

[oech3]

@xtqqczze Did you success to build uptime.exe with this commit?

[xtqqczze]

It does not build, uptime_with_file is configured out on Windows.