recipe_tryjob: Allow test bypass.

scripts/slave/recipes/infra/recipe_roll_tryjob.expected/tryjob.json

 [
   {
     "cmd": [
       "/opt/infra-tools/authutil",
       "token"
     ],
     "name": "Get auth token",
     "stdout": "/path/to/tmp/"
   },
   {
@@ skipping 125 matching lines @@
       "https://luci-config.appspot.com//_ah/api/config/v1/config_sets/projects%2Fbuild%2Frefs%2Fheads%2Fmaster/config/recipes.cfg",
       "--outfile",
       "/path/to/tmp/",
       "--headers-json",
       "{\"Authorization\": \"Bearer ya29.foobar\"}"
     ],
     "name": "Get project 'build' config 'recipes.cfg'"
   },
   {
     "cmd": [
+      "RECIPE_PACKAGE_REPO[depot_tools]/git_cl.py",
+      "description",
+      "-d",
+      "--rietveld",
+      "https://fake.code.review/12345678"
+    ],
+    "name": "git_cl description (build)",
+    "stdout": "/path/to/tmp/"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/git_footers.py",
+      "--json",
+      "/path/to/tmp/json"
+    ],
+    "name": "parse description",
+    "stdin": "",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@{}@@@",
+      "@@@STEP_LOG_END@json.output@@@"
+    ]
+  },
+  {
+    "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[SLAVE_BUILD]/build/build",
       "511"
     ],
     "name": "makedirs build directory",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@@@@",
       "@@@STEP_LOG_LINE@python.inline@import sys, os@@@",
@@ skipping 144 matching lines @@
       "simulation_test"
     ],
     "name": "build tests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]