Disable d8-worker-sharedarraybuffer test (fails on TSAN)

See http://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/4695/steps/Check%20%28flakes%29/logs/d8-worker-sharedarray..

BUG=v8:4306
R=machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
LOG=n

Review URL: https://codereview.chromium.org/1241713003

Cr-Commit-Position: refs/heads/master@{#29664}

test/mjsunit/mjsunit.status

@@ -248,6 +248,9 @@
   # BUG(chromium:508074). Remove this once the issue is fixed.
   'harmony/arrow-rest-params': [PASS, NO_VARIANTS],
   'harmony/rest-params': [PASS, ['no_snap == True', NO_VARIANTS]],
+
+  # BUG(v8:4306)
+  'd8-worker-sharedarraybuffer': [SKIP],
 }],  # ALWAYS
 
 ['novfp3 == True', {