The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/822dc3be40b955ffab77ca81f119ba67c6115ca7

commit 822dc3be40b955ffab77ca81f119ba67c6115ca7
Author: Jeffrey Li <lijeffrey@chromium.org>
Date: Thu Mar 22 20:30:09 2018

[Findit] Flake Analyzer - Use step_name for key of isolated_tests when collecting try job results

Flake try jobs get the isolate sha from the try job's 'isolated_tests' field, which uses the step
name as the key, not the test name.

Bug:  824899 
Change-Id: I7ef03502b3e6481026a5a0507133167a94cd31f8
Reviewed-on: https://chromium-review.googlesource.com/976373
Reviewed-by: Roberto Carrillo <robertocn@chromium.org>
Commit-Queue: Jeffrey Li <lijeffrey@chromium.org>

[modify] https://crrev.com/822dc3be40b955ffab77ca81f119ba67c6115ca7/appengine/findit/pipelines/flake_failure/test/get_isolate_sha_pipeline_test.py
[modify] https://crrev.com/822dc3be40b955ffab77ca81f119ba67c6115ca7/appengine/findit/pipelines/flake_failure/get_isolate_sha_pipeline.py