Consider make respective opcode for different IRs

[ChAoSUnItY]

While #196 was developing, it caught my eye that there are several opcodes are unused in phase 1 IR but phase 2 and vice versa, for example:

• OP_jump was never used in phase 1 IR (probably because goto and label definition is not yet implemented?)
• OP_define is later being added when register allocation is done, in other words, in phase 2 IR, while its actual usage is to allocate stack.
• OP_phi / OP_unwound_phi are only used in phase 1 and would get eliminated before passed into phase 2 IR.

It would be a good idea to separate these differences to 2 different set of opcode to not to be confused?