IndexedDB: Log exception messages

LayoutTests/storage/indexeddb/deleteIndex-bug110792-expected.txt

 Ensure IndexedDB's IDBObjectStore.deleteIndex() works if IDBIndex object has not been fetched - regression test for bug 110792.
 
 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 = "deleteIndex-bug110792.html"
 indexedDB.deleteDatabase(dbname)
 indexedDB.open(dbname, 1)
 
 onFirstUpgradeNeeded():
 db = event.target.result
 store = db.createObjectStore('store')
 store.createIndex('index', 'keyPath')
 
 closeAndReOpen():
 db.close()
 
 indexedDB.open(dbname, 2)
 
 onSecondUpgradeNeeded():
 db = event.target.result
 store = event.target.transaction.objectStore('store')
 store.deleteIndex('index')
 Expecting exception from store.index('index')
 PASS Exception was thrown.
 PASS code is DOMException.NOT_FOUND_ERR
 PASS ename is 'NotFoundError'
+Exception message: The specified index was not found.
 PASS successfullyParsed is true
 
 TEST COMPLETE