✅ test: check how big Instruction is

lunar_wave_vm/src/tests.rs

@@ -425,7 +425,7 @@ fn tailcall () {
 }
 
 #[test]
-fn value_size () {
+fn sizes () {
 	// Per https://www.lua.org/doc/jucs05.pdf,
 	// "The Implementation of Lua 5.0",
 	// 
@@ -479,4 +479,6 @@ fn value_size () {
 		let expected = 8;
 		assert! (sz == expected, "{sz} != {expected}");
 	}
+	
+	assert_eq! (size_of::<crate::instruction::Instruction> (), 8);
 }