Mark the futex mjsunit tests as non-deterministic

Bug: v8:7177
Change-Id: Ifd050eaf5196a2989011b12b8e81041fd598ae8e
Reviewed-on: https://chromium-review.googlesource.com/861166Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50494}

test/mjsunit/mjsunit.status

@@ -650,9 +650,9 @@
   # Skip tests that are known to be non-deterministic.
   'd8/d8-worker-sharedarraybuffer': [SKIP],
   'd8/d8-os': [SKIP],
+  'harmony/futex': [SKIP],
 
   # BUG(v8:7166).
-  'harmony/futex': [SKIP],
   'd8/enable-tracing': [SKIP],
 }],  # 'predictable == True'