RFR: 1587: Adding review comments should not mean approval status change [v3]

[Zhao Song]

> The issue here is ' if a user leaves additional comments using the "Review changes" dialog, and selects the "Comments", then their approval is considered revoked.'
> 
> I believe this happens because if we use "Review changes" to add a comment, it will add a review with `Review.Verdict.NONE` to our pr.  According to our current logic, this new review will cover old reviews, so the approval will be revoked.
> 
> I made changes to `CheckablePullRequest#filterActiveReviews`. Now If latest review is just a comment, the verdict will inherit from the previous review.

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

  Added a line breaker in CheckablePullRequest#filterActiveReviews and use pr.store() to do the test in testReviewCommentsAfterApprovedReview

-------------

Changes:
  - all: https://git.openjdk.org/skara/pull/1399/files
  - new: https://git.openjdk.org/skara/pull/1399/files/7abf5e32..473eec6f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1399&range=02
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1399&range=01-02

  Stats: 12 lines in 2 files changed: 1 ins; 5 del; 6 mod
  Patch: https://git.openjdk.org/skara/pull/1399.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1399/head:pull/1399

PR: https://git.openjdk.org/skara/pull/1399