OAK-1491: ObservationTest failure on Windows
- ObservationTest: fix timeout on slow machines by increasing timeout and disabling parallel test execution
- BackgroundObserverTest, ObservationRefreshTest: ensure observation revision queue is large enough to hold all items waited for as otherwise we end up in a deadlock when queue compacting kicks in as the pending events would only be generated on a subsequent commit.
- CompatibilityIssueTest: fix timeout on slow machines by increasing timeout

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1593213 13f79535-47bb-0310-9956-ffa450edef68