Indexed DB: Remove vendor prefix removal from tests

LayoutTests/storage/indexeddb/request-leak-expected.txt

 Verify that that requests weakly hold script value properties
 
 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 = "request-leak.html"
 indexedDB.deleteDatabase(dbname)
 indexedDB.open(dbname)
 
 prepareDatabase():
 db = event.target.result
 store = db.createObjectStore('store')
 store.put({value: 'value'}, 'key')
 
 onOpen():
 db = event.target.result
 tx = db.transaction('store')
 store = tx.objectStore('store')
 request = store.get('key')
 
 onTransactionComplete():
 db.close()
 PASS typeof request.result is "object"
 request.result.x = 123
 PASS request.result.x is 123
 request.result.leak = request
 observer = internals.observeGC(request)
 request = null
 gc()
 PASS observer.wasCollected is true
 PASS successfullyParsed is true
 
 TEST COMPLETE