Refactor UnwindInfo codes and frame_register (#2307)

* Refactor UnwindInfo codes and frame_register

* use isa word_size

* fix filetests

* Add comment about UnwindCode::PushRegister

cranelift/codegen/src/isa/unwind.rs

@@ -27,16 +27,12 @@ pub(crate) mod input {
         SaveRegister {
             offset: CodeOffset,
             reg: Reg,
+            stack_offset: u32,
         },
         RestoreRegister {
             offset: CodeOffset,
             reg: Reg,
         },
-        SaveXmmRegister {
-            offset: CodeOffset,
-            reg: Reg,
-            stack_offset: u32,
-        },
         StackAlloc {
             offset: CodeOffset,
             size: u32,
@@ -64,5 +60,6 @@ pub(crate) mod input {
         pub(crate) prologue_unwind_codes: Vec<UnwindCode<Reg>>,
         pub(crate) epilogues_unwind_codes: Vec<Vec<UnwindCode<Reg>>>,
         pub(crate) function_size: CodeOffset,
+        pub(crate) word_size: u8,
     }
 }