In builtin JS, we have bunch of
if (object === null || object === @undefined)
thing. Previously, this is written as follows.
if (object == null)
However, the above one recognizes document.all as null/undefined due to its masquerade.
So, they are rewritten.
But the above thing is,
1. From JS developer, it looks very storange because it seems `== null` is better.
2. It bloats bytecodes, effectively prevents us from inlining. Keep builtin JS function small is a bit important in terms of inlining.
So, to make the meaning explicit and tighten bytecode size, we would like to introduce a new bytecode, op_is_undefined_or_null_ignoring_masquerade.