Reduce processing interval for page-fetch-backlog tests
Reduce processing interval for page-fetch-backlog tests

- it seems to fail occasionally (failed once going by 15 runs I did)
- I couldn't get it to fail at this time, but no doubt it'll eventually fail given the nature of the JS event loop and "waiting"
- nice to get a test that doesn't rely on waiting

WorldBrain/WebMemex,WorldBrain/WebMemex