Re-enable VolumeManagerTest.OnRenameEvent_Completed

After CL:1530385, this test's flake rate is expected to reduce to much
less than 1 in 1000 test runs. See crbug.com/943570#c7 for rationale.

Tbr: lucmult@
Bug: 938755
Change-Id: Id304323b749e4356d777b6b265141dd48dfa1391
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531933
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Stuart Langley <slangley@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642460}
1 file changed