Function emit_jump 

pub fn emit_jump(
    ctx: &mut EmitContext,
    pipeline: &mut CodegenPipeline,
    builder: &mut FunctionBuilder<'_>,
    vmctx: Value,
    gc_sig: SigRef,
    tree: &CoreExpr,
    label: &JoinId,
    arg_indices: &[usize],
) -> Result<SsaVal, EmitError>

Emits a Jump expression. Jump { label, args } transfers control to the join point block.