[test] Skip flaky test on windows

NOTRY=true

Bug: v8:7492
Change-Id: Ie25281f8efa30d14574c7b53b4ab8a22d1344535
Reviewed-on: https://chromium-review.googlesource.com/934847Reviewed-by: Fadi Meawad <fmeawad@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51531}

test/unittests/unittests.status

@@ -3,4 +3,8 @@
 # found in the LICENSE file.
 
 [
+['system == windows', {
+  # BUG(7492).
+  'ThreadTicks.ThreadNow': [SKIP],
+}],  # 'system == windows'
 ]