Revamping the tests

[aagusuab]

• Remove unnecessary nestings on the test
• Namespace cannot be removed using Corev1.Namespace.Delete(). Remove all of the instances of this.
• Remove anonymous functions within the Contexts, Its, etc.
• Remove 1 to 1 nesting

[ryanzhang-oss]

I am not sure if it's already included, here are something I observed

1. remove all nested "by" function
2. since delete namespace doesn't work, the test cannot rely on it to clean up
3. an IT actually does something, it's not an IT if it's just a verification
4. make the style consistent at least within one test file.