ZJIT: Inline `gen_defined`'s check for each op type

- [ ] `DEFINED_IVAR`
- [ ] `DEFINED_GVAR`
- [ ] `DEFINED_CVAR`
- [ ] `DEFINED_CONST` & `DEFINED_CONST_FROM`
- [ ] `DEFINED_FUNC`
- [ ] `DEFINED_METHOD`
- [ ] `DEFINED_ZSUPER`
- [ ] `DEFINED_REF`