Indexed DB: Remove vendor prefix removal from tests

LayoutTests/storage/indexeddb/exceptions-expected.txt

 Test that expected exceptions are thrown per IndexedDB spec.
 
 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 = "exceptions.html"
 indexedDB.deleteDatabase(dbname)
 indexedDB.open(dbname)
 store = db.createObjectStore('store')
 index = store.createIndex('index', 'id')
 store.put({id: 'a'}, 1)
 store.put({id: 'b'}, 2)
 store.put({id: 'c'}, 3)
 store.put({id: 'd'}, 4)
 store.put({id: 'e'}, 5)
@@ skipping 604 matching lines @@
 If the requested object store is not in this transaction's scope.
 Expecting exception from db.transaction('store').objectStore('otherStore')
 PASS Exception was thrown.
 PASS code is DOMException.NOT_FOUND_ERR
 PASS ename is 'NotFoundError'
 Exception message: Failed to execute 'objectStore' on 'IDBTransaction': The specified object store was not found.
 PASS successfullyParsed is true
 
 TEST COMPLETE