Fix hasFlags method in IntentAssert

Android has same values for flags `FLAG_ACTIVITY_MULTIPLE_TASK` and
`FLAG_RECEIVER_NO_ABORT`. Hence, any invocation of `hasFlags` resulted
in IllegalStateException being thrown.

Try, for example:
```java
  @Test
  public void test() {
    assertThat(new Intent().addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT))
        .hasFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
  }
```

I believe we also need a project with integration tests. Where this test could be written.
I personally created one to test your code from master branch. But I do not submit it here: it uses robolectric. Should I submit it?
I really do not know whether this change will break something in other place. The project definitely lacks tests IMHO...