Correct IndexedDB test issues

This contains fixes for:

idbdatabase_close2.htm -  test assumed no versionchange, spec requires it
idbdatabase_createObjectStore9-invalidparameters.htm - was assuming exception priority (unspecified)
idbindex-multientry-big.htm - was assuming transaction sequencing (spec allows UA flexibility)
idbobjectstore_createIndex6-event_order.htm - correct expected exception type per spec