Instrinsic jump to $ssp

[IGI-111]

To use LDC we need a way to jump into the loaded code like so: https://github.com/FuelLabs/ldc-testing/blob/7d188823b2fa27a027b3733d7deb332f30ff1524/test-contract/src/main.sw#L33

We should add a __jump_to_ssp intrinsic to make this possible without having to allow control flow opcodes in asm blocks.