Cleaning up the PolicyFile editors usage in Sentry end to end tests - (SENTRY-6)

[Sravya Tirukkovalur]

Hi all,

The complete patch where all the end to end tests are changed to use
PolicyFile for editing the policy files is ready. A friendly reminder that
the review is on RB here:
https://reviews.apache.org/r/14096/

Thanks!
-- 
Sravya Tirukkovalur