Disable 3 ExtensionServiceTestSupervised tests on memory bots.
Disable 3 ExtensionServiceTestSupervised tests on memory bots.

There is likely a timing issue causing the text expectations to fail
when run on such slow bots.

BUG=567866
TBR=treib@chromium.org

Review URL: https://codereview.chromium.org/1513523002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#363873}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk