[test] Skip test on gc fuzzer

TBR=marja@chromium.org

Bug: v8:8286
Change-Id: I862d557c22e373c81171f0bb33b23d37157fbccd
Reviewed-on: https://chromium-review.googlesource.com/c/1273120Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56527}

test/mjsunit/mjsunit.status

@@ -718,6 +718,9 @@
   'regress/regress-trap-allocation-memento': [PASS, FAIL],
   'regress/regress-unlink-closures-on-deopt': [PASS, FAIL],
   'shared-function-tier-up-turbo': [PASS, FAIL],
+
+  # https://crbug.com/v8/8286
+  'harmony/weakrefs/basics': [SKIP],
 }],  # 'gc_fuzzer'
 
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