Refactor stages 1, 2 and test_api overhaul.

scripts/slave/recipes/bisect_test/example_bisect_results.expected/failed_direction_test.json

 [
   {
     "cmd": [
       "git",
       "update-ref",
       "refs/heads/master",
       "refs/remotes/origin/master"
     ],
     "cwd": "[TMP_BASE]/bogus_tmp_1",
     "name": "git update-ref"
@@ skipping 114 matching lines @@
       "@@@STEP_LOG_END@Debug Good Revision DEPS@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[build::perf_dashboard]/resources/post_json.py"
     ],
     "name": "Post bisect results",
-    "stdin": "{\"data\": {\"aborted_reason\": \"The metric values for the initial \\\"good\\\" and \\\"bad\\\" revisions match the expected direction of improvement. Thus, likely represent an improvement and not a regression.\", \"bad_revision\": \"deadbeef\", \"bisect_bot\": \"linux_perf_tester\", \"bug_id\": null, \"buildbot_log_url\": \"http://build.chromium.org/p/chromium/builders//builds/\", \"change\": null, \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"culprit_data\": null, \"good_revision\": \"c001c0de\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"revision_data\": [], \"score\": 0, \"status\": \"completed\", \"test_type\": \"perf\", \"try_job_id\": null, \"warnings\": [\"This is a demo warning\"]}, \"url\": \"https://chromeperf.appspot.com/post_bisect_results\"}",
+    "stdin": "{\"data\": {\"aborted_reason\": \"The metric values for the initial \\\"good\\\" and \\\"bad\\\" revisions match the expected direction of improvement. Thus, likely represent an improvement and not a regression.\", \"bad_revision\": \"deadbeef\", \"bisect_bot\": \"linux_perf_tester\", \"bug_id\": null, \"buildbot_log_url\": \"http://build.chromium.org/p/chromium/builders//builds/\", \"change\": null, \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"culprit_data\": null, \"good_revision\": \"c001c0de\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"revision_data\": [], \"status\": \"completed\", \"test_type\": \"perf\", \"try_job_id\": null, \"warnings\": [\"This is a demo warning\"]}, \"url\": \"https://chromeperf.appspot.com/post_bisect_results\"}",
     "stdout": "/path/to/tmp/json",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"status_code\": 200@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]