RISC-V: Lower JalrImm, JalrAbsolute, JAbsolute, Jal

Closes RV-571

What

Lowers opcode JalrImm, JalrAbsolute, JAbsolute, Jal

Why

Part of the effort to enable internal opcodes to be runnable in both interpreted mode and jitted mode

How

Moved the jump opcodes to branching.rs supporting ICB. Enabled to_lowering of the opcodes.

Manually Testing

make -C src/riscv all

Benchmarking

	master	This MR	Improvement
M2 Macbook Pro	6.226 TPS	6.220 TPS	-0.09%
Benchmark Machine	3.790 TPS	3.746 TPS	-0.91%

Regressions

Tasks for the Author

• Link all Linear issues related to this MR using magic words (e.g. part of, relates to, closes).
• Eliminate dead code and other spurious artefacts introduced in your changes.
• Document new public functions, methods and types.
• Make sure the documentation for updated functions, methods, and types is correct.
• Add tests for bugs that have been fixed.
• Put in reasonable effort to ensure that CI will pass.
  • make -C src/riscv
  • dune build src/lib_riscv
  • dune build src/rust_deps
• Benchmark performance and populate the table above if needed.
• Explain changes to regression test captures when applicable.
• Write commit messages to reflect the changes they're about.
• Self-review your changes to ensure they are high-quality.
• Complete all of the above before assigning this MR to reviewers.