Fix LP 1386968

* move things around to make recordingStorage simpler
* break out the blobs file map into its own type as that is the bit we want to interrogate after the test run
* add more locks, that always seems to help

Passes several runs of stress.bash without puking, race detector is happy as well.
responding to review feedback
Merge pull request #1042 from davecheney/208-fix-lp-1386968

Fix LP 1386968

* move things around to make recordingStorage simpler
* break out the blobs file map into its own type as that is the bit we want to interrogate after the test run
* add more locks, that always seems to help

Passes several runs of stress.bash without puking, race detector is happy as well.