Update size check

Author: rtfeldman

test/serialization_size_check.zig

@@ -31,7 +31,7 @@ const expected_safelist_u8_size = 24;
 const expected_safelist_u32_size = 24;
 const expected_safemultilist_teststruct_size = 24;
 const expected_safemultilist_node_size = 24;
-const expected_moduleenv_size = 712; // Platform-independent size (includes padding for removed fields)
+const expected_moduleenv_size = 704; // Platform-independent size
 const expected_nodestore_size = 96; // Platform-independent size
 
 // Compile-time assertions - build will fail if sizes don't match expected values