LobStorageBackend is only ever constructed from Database, so let's use it directly

This is a cleanup targetted at allowing us to fix a deadlock issue.

   //## Java 1.6 ##
comments. We no longer need them, since we depend on Java6 or better now.

fix connection leaks in the testing code. Prevents my machine from running out of sockets during soak tests

fix some connection leaks, and an assignment error in testRecoverLobInDatabase() where it was creating the statement from the wrong connection

make sure to clean up the CancelThread. Sometimes this test fails and then the cancel thread hangs around.

The optimization for IN(...) queries combined with OR could result in a strange exception of the type "column x must be included in the group by list".

The optimization for IN(...) queries combined with OR could result in a strange exception of the type "column x must be included in the group by list".

Fix bug in optimising SELECT * FROM A WHERE X=1 OR X=2 OR X=3 into SELECT * FROM A WHERE X IN (1,2,3)