Don't DCHECK that the weak closure wasn't yet overapproximated
Don't DCHECK that the weak closure wasn't yet overapproximated

Maybe it was overapproximated via the idle notification already, so just
don't retry in that case

BUG=chromium:469023
R=hpayer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1025603003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#27335}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh