dd: support wasm32-wasip1

[pocopepe]

Closes #12211

adds dd to feat_wasm. wasi-libc has no LC_CTYPE so gated that, and the windows stdin detection was leaking into wasi so scoped it under cfg(windows). unit tests pass under wasmtime. runtime still panics on thread::spawn though, separate issue. happy to open a follow-up issue for the thread::spawn runtime problem if that'd be useful

[xtqqczze]

I think StdinFile might work with wasi, but only with nightly compiler: 43ce291

[oech3]

Or try to open /dev/stdin.

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/resolution (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/expand/bounded-memory is now passing!
Congrats! The gnu test tests/printf/printf-surprise is now passing!

[xtqqczze]

I've authored a commit that uses StdinFile on nightly: 2371174