[SOL] Implement JMP32 instruction class

[LucasSte]

Summary

We aim to support eBPFv3 with sBPF v3, so we can bring back the JMP32 instruction class that I removed in #80 to implement the PQR class.

Changes

1. Bring back JMP32, behind a feature gate.
2. Add codegen, assembler and disassembler tests.
3. Fix the analyzeBranch function and reverseBranch with the new instructions.
4. Fix the lowering of select and branch instructions to work with JMP32.