[Test] Mark flaky test cctest/test-lockers/LockAndUnlockDifferentIsolates for real

BUG=v8:4642
LOG=N
NOTRY=true
TBR=machenbach@chromium.org,mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1549663004 .

Cr-Commit-Position: refs/heads/master@{#33025}

test/cctest/cctest.status

@@ -244,7 +244,7 @@
   'test-api/MultipleIsolatesOnIndividualThreads': [PASS, NO_VARIANTS],
 
   # BUG(v8:4642).
-  'test-lockers/LockAndUnlockDifferentIsolates': [PASS, FLAKY],
+  'test-lockers/LockAndUnlockDifferentIsolates': [PASS, NO_VARIANTS],
 }],  # 'system == windows'
 
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