Retry more carefully

When we notice that notifications ran too quickly, start over from
the beginning. Just retrying the notiofications was ineffective,
presumably because we already triggered a GC. but it somehow
completed before we looked for blocking behavior.

Test: Treehugger, some manual testing with code changes.
Bug: 190148586
Change-Id: Ic4689165c5f37535b6ba0e05f03584cdc1d04c40
1 file changed