H2 locking errors due to autocommit=false in non-XA mode

There is a H2 bug which manifests itself under Tomcat when using WebEngine.

The problem is that the XAConnection used by VCS in XA mode (start/end/commit) are not reset correctly to autocommit=true after they've been used, which means that a subsequent non-transactional use of the XAConnection will fail to commit its work. With H2 this means that any other connection to the database try to acquire a lock on any modified table and fail, resulting in messages like:
org.h2.jdbc.JdbcSQLException. message: Timeout trying to lock table HIERARCHY