Remove non-WASI code

crates/plugin_runtime/build.rs

@@ -1,23 +0,0 @@
-use std::process::Command;
-
-fn main() {
-    let cwd = std::env::current_dir().unwrap();
-    let plugin_workspace = cwd.join("plugin").join("Cargo.toml");
-    Command::new("cargo")
-        .args(&["clean", "--manifest-path"])
-        .arg(&plugin_workspace)
-        .status()
-        .unwrap();
-    Command::new("cargo")
-        .args(&[
-            "build",
-            "--release",
-            "--target",
-            "wasm32-unknown-unknown",
-            "--manifest-path",
-        ])
-        .arg(&plugin_workspace)
-        .status()
-        .unwrap();
-    println!("cargo:warning=recompiling plugins")
-}