machinst x64: implement enough to support branch tables;

cranelift/codegen/src/isa/aarch64/inst/mod.rs

@@ -875,8 +875,7 @@ pub enum Inst {
         data: u64,
     },
 
-    /// Jump-table sequence, as one compound instruction (see note in lower.rs
-    /// for rationale).
+    /// Jump-table sequence, as one compound instruction (see note in lower_inst.rs for rationale).
     JTSequence {
         info: Box<JTSequenceInfo>,
         ridx: Reg,

cranelift/codegen/src/isa/aarch64/lower_inst.rs

@@ -2380,7 +2380,7 @@ pub(crate) fn lower_branch<C: LowerCtx<I = Inst>>(
                     info: Box::new(JTSequenceInfo {
                         targets: jt_targets,
                         default_target,
-                        targets_for_term: targets_for_term,
+                        targets_for_term,
                     }),
                 });
             }