Reorganize wasi-misc-tests. (#575)

* Reorganize wasi-misc-tests.

Move wasi-misc-tests out of wasi-common, to break a dependency cycle;
previously, wasmtime-* depended on wasi-common, but wasi-common
dev-dependended on wasmtime-*.

Now, wasi-common no longer dev-depends on wasmtime-*; instead, the
tests are in their own crate which depends on wasi-common and on
wasmtime-*.

Also, rename wasi-misc-tests to wasi-tests for simplicity.

This also removes the "wasm_tests" feature; it's replaced by the
"test-programs" feature.

* Update the CI script to use the new feature name.

* Update the CI script to use the new feature name in one more place.

* Change a `write!` to a `writeln!`.

crates/test-programs/wasi-tests/src/bin/close_preopen.rs

@@ -0,0 +1,83 @@
+use libc;
+use more_asserts::assert_gt;
+use std::{env, mem, process};
+use wasi::wasi_unstable;
+use wasi_tests::open_scratch_directory;
+use wasi_tests::wasi_wrappers::wasi_fd_fdstat_get;
+
+unsafe fn test_close_preopen(dir_fd: wasi_unstable::Fd) {
+    let pre_fd: wasi_unstable::Fd = (libc::STDERR_FILENO + 1) as wasi_unstable::Fd;
+
+    assert_gt!(dir_fd, pre_fd, "dir_fd number");
+
+    // Try to close a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_close(pre_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "closing a preopened file descriptor",
+    );
+
+    // Try to renumber over a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_renumber(dir_fd, pre_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "renumbering over a preopened file descriptor",
+    );
+
+    // Ensure that dir_fd is still open.
+    let mut dir_fdstat: wasi_unstable::FdStat = mem::zeroed();
+    let mut status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the scratch directory"
+    );
+    assert_eq!(
+        dir_fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+
+    // Try to renumber a preopened directory handle.
+    assert_eq!(
+        wasi_unstable::fd_renumber(pre_fd, dir_fd),
+        Err(wasi_unstable::ENOTSUP),
+        "renumbering over a preopened file descriptor",
+    );
+
+    // Ensure that dir_fd is still open.
+    status = wasi_fd_fdstat_get(dir_fd, &mut dir_fdstat);
+    assert_eq!(
+        status,
+        wasi_unstable::raw::__WASI_ESUCCESS,
+        "calling fd_fdstat on the scratch directory"
+    );
+    assert_eq!(
+        dir_fdstat.fs_filetype,
+        wasi_unstable::FILETYPE_DIRECTORY,
+        "expected the scratch directory to be a directory",
+    );
+}
+
+fn main() {
+    let mut args = env::args();
+    let prog = args.next().unwrap();
+    let arg = if let Some(arg) = args.next() {
+        arg
+    } else {
+        eprintln!("usage: {} <scratch directory>", prog);
+        process::exit(1);
+    };
+
+    // Open scratch directory
+    let dir_fd = match open_scratch_directory(&arg) {
+        Ok(dir_fd) => dir_fd,
+        Err(err) => {
+            eprintln!("{}", err);
+            process::exit(1)
+        }
+    };
+
+    // Run the tests.
+    unsafe { test_close_preopen(dir_fd) }
+}