fix DatabaseConstraint exceptions upon DB Cleanup and pathological Biomodel saves.

[jcschaff]

Background - two problems - one on save, one on delete/cleanup

• ~260 times a day, the health monitor saves the exact same BioModel (same XML) with cleared biomodel key.
  • about once a day it fails with (java.sql.SQLIntegrityConstraintViolationException: ORA-02291: integrity constraint).
  • All other invocations of this save passes.
  • Interestingly, the BioModel which the health service saves is always loaded from the same XML file (https://github.com/virtualcell/vcell/blob/master/vcell-api/src/main/resources/TestTemplate.vcml) but with the top-level version cleared (e.g. it has no biomodel_id).
• incomplete periodic cleanup of orphaned records (once a day).
  • cbit.vcell.modeldb.DatabaseServerImpl.cleanupDatabase(DatabaseServerImpl.java:133) fails with a complementary failure (java.sql.SQLIntegrityConstraintViolationException: ORA-02292: integrity constraint (VCELL.SYS_C0022037) violated - child record found)
  • the order of the delete operations should have prevented such a failure.

[jcschaff]

Strategy

• test BioModel saves with randomizedBioModel keys to try to make the save problem more reproducible.
• review DatabaseServerImpl.cleanupDatabase() to look for problems and add logging as needed to help diagnose.