wasm_interp: implement function call (no arguments yet!)

crates/wasm_module/src/opcodes.rs

@@ -1,3 +1,5 @@
+use crate::Serialize;
+
 use super::parse::{Parse, ParseError, SkipBytes};
 
 #[repr(u8)]
@@ -495,3 +497,9 @@ impl SkipBytes for OpCode {
         Ok(())
     }
 }
+
+impl Serialize for OpCode {
+    fn serialize<T: crate::SerialBuffer>(&self, buffer: &mut T) {
+        (*self as u8).serialize(buffer)
+    }
+}