Adding config step to output the bisect config dictionary.

scripts/slave/recipe_modules/auto_bisect/example.expected/missing_vars_entry.json

 [
   {
     "cmd": [
+      "echo",
+      "{'good_revision': '314015', 'builder_host': 'master4.golo.chromium.org', 'truncate_percent': '0', 'metric': 'mean_input_event_latency/mean_input_event_latency', 'max_time_minutes': '5', 'builder_port': '8341', 'bug_id': '', 'command': 'src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases', 'skip_gclient_ops': 'True', 'dummy_builds': 'True', 'repeat_count': '2', 'test_type': 'perf', 'gs_bucket': 'chrome-perf', 'bad_revision': '314017'}"
+    ],
+    "name": "config"
+  },
+  {
+    "cmd": [
       "git",
       "log",
       "--format=hash:%H",
       "--grep",
       "Cr-Commit-Position: refs/heads/master@{#314017}",
       "-1",
       "refs/heads/master"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "resolving commit_pos 314017",
@@ skipping 548 matching lines @@
     "cwd": "[SLAVE_BUILD]/src/v8",
     "name": "Expanding revision range for revision 004 on depot v8",
     "stdout": "/path/to/tmp/"
   },
   {
     "name": "$final_result",
     "reason": "DEPS file does not contain entry for v8_revision",
     "status_code": 1
   }
 ]