Reuse the workspace target for fixture builds

host/tests/hook_git.rs

@@ -24,10 +24,7 @@ fn git(cwd: &Path, args: &[&str]) {
 async fn several_mb_git_push() {
     static BUILT: OnceLock<std::path::PathBuf> = OnceLock::new();
     let component = BUILT.get_or_init(|| {
-        let target = std::path::PathBuf::from(
-            std::env::var_os("CARGO_TARGET_DIR")
-                .expect("CARGO_TARGET_DIR must name the executor's shared target directory"),
-        );
+        let target = Path::new(env!("CARGO_TARGET_TMPDIR")).parent().unwrap();
         let userland = Path::new(env!("CARGO_MANIFEST_DIR")).join("../userland");
         if !userland.join("cwd-init/init.o").is_file() {
             assert!(
@@ -46,7 +43,7 @@ async fn several_mb_git_push() {
                 .arg(manifest)
                 .current_dir(&userland)
                 .args(["--target", "wasm32-wasip2", "--target-dir"])
-                .arg(&target)
+                .arg(target)
                 .args(["-j", "2", "--locked"])
                 .status()
                 .unwrap()