the createCustomEvent function's pupose is to create customEvents
even on browsers where `CustomEvent` is not a constructor,
`CustomEvent` is currently available in all supported browsers (since
IE11 support has ended), so remove the function as it is no longer
needed
PR Close#44703
1. update jasmine to 3.5
2. update @types/jasmine to 3.5
3. update @types/jasminewd2 to 2.0.8
Also fix several cases, the new jasmine 3 will help to create test cases correctly,
such as in the `jasmine 2.x` version, the following case will pass
```
expect(1 == 2);
```
But in jsamine 3, the case will need to be
```
expect(1 == 2).toBeTrue();
```
PR Close#34625
This PR was merged without API docs and general rollout plan.
We can't release this as is in 5.1 without a plan for documentation, cli integration, etc.
