Make parallel Sys STM test negative on macOS ARM64

Author: jmid

src/sys/stm_tests.ml

@@ -322,15 +322,13 @@ let run_cmd cmd =
 
 let uname_os () = run_cmd "uname -s"
 
-let arch () = run_cmd "opam var arch"
-
 module Sys_seq = STM_sequential.Make(SConf)
 module Sys_dom = STM_domain.Make(SConf)
 
 ;;
 QCheck_base_runner.run_tests_main [
     Sys_seq.agree_test              ~count:1000 ~name:"STM Sys test sequential";
-    if Sys.unix && (uname_os () = Some "Linux" || arch () = Some "arm64")
+    if Sys.unix && uname_os () = Some "Linux"
     then Sys_dom.agree_test_par     ~count:200  ~name:"STM Sys test parallel"
     else Sys_dom.neg_agree_test_par ~count:1000 ~name:"STM Sys test parallel"
   ]