[MemSheriff] Suppress leak for PPS tests
[MemSheriff] Suppress leak for PPS tests

BUG=598364
TBR=tommycli@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1837833002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#383653}

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