TEMPORARY: inherit stdio for the wasi ctx

this is unfortunate but the poll_oneoff test insists on polling on stdio
handles. to undo this temporary fix later, lets rewrite the test to open
some regular files from the scratch directory and poll on them instead.

crates/test-programs/tests/wasm_tests/runtime.rs

@@ -5,8 +5,10 @@ use wasi_c2::virt::pipe::{ReadPipe, WritePipe};
 use wasmtime::{Linker, Module, Store};
 
 pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> anyhow::Result<()> {
+    /*
     let stdout = WritePipe::new_in_memory();
     let stderr = WritePipe::new_in_memory();
+    */
 
     let r = {
         let store = Store::default();
@@ -15,12 +17,7 @@ pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> any
         // Additionally register any preopened directories if we have them.
         let mut builder = wasi_c2::WasiCtx::builder();
 
-        builder = builder
-            .arg(bin_name)?
-            .arg(".")?
-            .stdin(Box::new(ReadPipe::from(Vec::new())))
-            .stdout(Box::new(stdout.clone()))
-            .stderr(Box::new(stderr.clone()));
+        builder = builder.arg(bin_name)?.arg(".")?.inherit_stdio();
 
         if let Some(workspace) = workspace {
             println!("preopen: {:?}", workspace);
@@ -46,6 +43,7 @@ pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> any
     match r {
         Ok(()) => Ok(()),
         Err(trap) => {
+            /*
             let stdout = stdout
                 .try_into_inner()
                 .expect("sole ref to stdout")
@@ -60,6 +58,7 @@ pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> any
             if !stderr.is_empty() {
                 println!("guest stderr:\n{}\n===", String::from_utf8_lossy(&stderr));
             }
+            */
             Err(trap.context(format!("error while testing Wasm module '{}'", bin_name,)))
         }
     }