Move encapsulated environment out of ScriptFnDef.

src/tests.rs

@@ -31,6 +31,14 @@ fn check_struct_sizes() {
         size_of::<Option<ast::Stmt>>(),
         if IS_32_BIT { 12 } else { 16 }
     );
+    assert_eq!(
+        size_of::<CallableFunction>(),
+        if IS_32_BIT { 12 } else { 24 }
+    );
+    assert_eq!(
+        size_of::<module::FuncInfo>(),
+        if IS_32_BIT { 16 } else { 32 }
+    );
 
     #[cfg(target_pointer_width = "64")]
     {