[Findit] Use step level analysis to exclude flaky test failures.

appengine/findit/waterfall/test/data/m_b_125_abc_test.json

Index: appengine/findit/waterfall/test/data/m_b_125_abc_test.json
diff --git a/appengine/findit/waterfall/test/data/m_b_125_abc_test.json b/appengine/findit/waterfall/test/data/m_b_125_abc_test.json
new file mode 100644
index 0000000000000000000000000000000000000000..f85ec5dfffe55625085b22f303efb0ce83b3be76
--- /dev/null
+++ b/appengine/findit/waterfall/test/data/m_b_125_abc_test.json
@@ -0,0 +1,46 @@
+{
+    "timestamp": "2015-05-20 02:54:17.691218",
+    "gtest_results": "invalid",
+    "version": 1,
+    "build_properties": {
+        "parent_wk_revision": null,
+        "parent_got_v8_revision": null,
+        "parent_got_swarming_client_revision": null,
+        "parent_build_archive_url": null,
+        "git_revision": null,
+        "recipe": null,
+        "parent_revision": null,
+        "parent_slavename": null,
+        "project": null,
+        "parent_scheduler": null,
+        "parentname": null,
+        "parent_buildnumber": null,
+        "slavename": null,
+        "blamelist": [],
+        "branch": null,
+        "patchset": null,
+        "issue": null,
+        "revision": null,
+        "workdir": null,
+        "repository": null,
+        "buildername": null,
+        "parent_try_job_key": null,
+        "mastername": null,
+        "parent_got_webkit_revision": null,
+        "parent_builddir": null,
+        "parent_branch": null,
+        "scheduler": null,
+        "requester": null,
+        "parent_cr_revision": null,
+        "rietveld": null,
+        "parent_got_nacl_revision": null,
+        "parent_buildername": null,
+        "parent_got_revision": null,
+        "buildnumber": null,
+        "requestedAt": null,
+        "patch_url": null,
+        "parent_git_number": null,
+        "parentslavename": null
+    },
+    "test_exe": "unittests"
+}