Set LC_ALL instead of LANG

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

test/blackbox-tests/cram.mll

@@ -155,7 +155,7 @@ and postprocess_ext tbl b = parse
           exit 0;
       end;
       let env =
-        Env.add Env.initial ~var:"LANG" ~value:"C"
+        Env.add Env.initial ~var:"LC_ALL" ~value:"C"
         |> Env.to_unix
       in
       Test_common.run_expect_test expect_test ~f:(fun file_contents lexbuf ->