Make s390x non-clobber-only vector register support unstable

Author: taiki-e

src/inline_asm.rs

@@ -462,8 +462,12 @@ impl<'tcx> InlineAssemblyGenerator<'_, 'tcx> {
         let mut slots_output = vec![None; self.operands.len()];
 
         let new_slot_fn = |slot_size: &mut Size, reg_class: InlineAsmRegClass| {
-            let reg_size =
-                reg_class.supported_types(self.arch).iter().map(|(ty, _)| ty.size()).max().unwrap();
+            let reg_size = reg_class
+                .supported_types(self.arch, true)
+                .iter()
+                .map(|(ty, _)| ty.size())
+                .max()
+                .unwrap();
             let align = rustc_abi::Align::from_bytes(reg_size.bytes()).unwrap();
             let offset = slot_size.align_to(align);
             *slot_size = offset + reg_size;