Fix last flaky test (that I know of).  The problem was we were asserting that something existed in a child injector (through inference, by checking it was in the parent blacklist), but if GC ran it could have been ejected from the parent blacklist (since the child injector isn't strongly referenced anywhere).

There's an actual problem here that we should fix (remove items from the parent blacklist immediately if the child injector fails to create itself), but before fixing that we can at least make the test not flake.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=71369181
Merge pull request #821 from google/moe_writing_branch_from_76be88e8140f77a25824f5deb67bb13b8e5dabc6

Merge internal changes