auto-triage: Refactor issue updating
auto-triage: Refactor issue updating

Split _GetPreproccessedRegressions so we can make sure only call sheriff-config once on
each test. Fixing UpdateIssue to update anomalies before early return.

Bug: chromium:1088359
Change-Id: I030ec9dde3bfc35eea1f282ec1fd623a674c0e47
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/2224076
Commit-Queue: Chenlin Fan <ade7e59805b81f027d537665b2c12c1956198b97@chromium.org>
Reviewed-by: Dean Berris <34a37f59e4ade3cf49221306f04217acf3e86255@chromium.org>
Auto-Submit: Chenlin Fan <ade7e59805b81f027d537665b2c12c1956198b97@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult