fix(compiler): Correct IR instruction names in assert functions

Fix compilation errors in assert-signer, assert-writable, and assert-owner:
- JmpNZ → JumpIf (correct instruction name)
- CmpEq → Eq (correct instruction name)
- new_label() → new_label("prefix") (requires prefix argument)

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Co-Authored-By: Claude <[email protected]>

Author: 0xrinegade