Xinyu Wu

Fix indeterminate map ordering that may causes Sweep2Test to fail

1

The test `org.apache.jackrabbit.oak.plugins.document.Sweep2Test#testSweep2Uncommitted` can fail based on the order of iteration in `HashMap`. I found the issue using [NonDex](https://github.com/TestingResearchIllinois/NonDex): ``` mvn install -DskipTests -pl oak-store-document -am mvn -pl oak-store-document edu.illinois:nondex-maven-plugin:1.1.2:nondex...