ISLE: Resolve remaining x64 overlap errors (#4977)

Resolve overlap errors with the x64 backend.

cranelift/codegen/src/machinst/isle.rs

@@ -718,6 +718,11 @@ macro_rules! isle_prelude_methods {
             }
         }
 
+        #[inline]
+        fn tls_model(&mut self, _: Type) -> TlsModel {
+            self.flags.tls_model()
+        }
+
         #[inline]
         fn tls_model_is_elf_gd(&mut self) -> Option<()> {
             if self.flags.tls_model() == TlsModel::ElfGd {