IndexedDB: Log exception messages

LayoutTests/storage/indexeddb/intversion-close-in-oncomplete-expected.txt

 Call db.close() in the complete handler for a version change transaction, before the success event associated with the open call fires
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
 indexedDB = self.indexedDB || self.webkitIndexedDB || self.mozIndexedDB || self.msIndexedDB || self.OIndexedDB;
 
 dbname = "intversion-close-in-oncomplete.html"
 indexedDB.deleteDatabase(dbname)
 request = indexedDB.open(dbname, 7)
 
 upgradeNeeded():
 db = event.target.result
 PASS event.newVersion is 7
 db.createObjectStore('os')
 transaction = event.target.transaction
 
 transaction.oncomplete:
 sawTransactionComplete = true
 db.close()
 
 openError():
 PASS sawTransactionComplete is true
 PASS event.target.result is null
 PASS event.target.error.name is "AbortError"
 Expecting exception from transaction = db.transaction('os', 'readwrite')
 PASS Exception was thrown.
 PASS code is DOMException.INVALID_STATE_ERR
 PASS ename is 'InvalidStateError'
+Exception message: The database connection is closing.
 PASS successfullyParsed is true
 
 TEST COMPLETE