Roll recipe dependencies (nontrivial).

scripts/slave/recipes/client.fletch.recipe_autogen.expected/cross_dartino_linux_arm.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': '.DEPS.git', 'managed': True, 'name': 'sdk', 'url': 'https://github.com/dartino/sdk.git'}]",
       "--patch_root",
       "sdk",
@@ skipping 77 matching lines @@
       "[SLAVE_BUILD]/sdk/third_party/dart/tools/task_kill.py",
       "--kill_browsers=True"
     ],
     "cwd": "[SLAVE_BUILD]/sdk",
     "env": {
       "BUILDBOT_JAVA_HOME": "[SLAVE_BUILD]/sdk/third_party/java/linux/j2sdk"
     },
     "name": "Taskkill (2)"
   },
   {
-    "cmd": [],
     "name": "trigger",
     "trigger_specs": [
       {
         "builder_name": "target-dartino-linux-release-arm"
       },
       {
         "builder_name": "target-dartino-linux-debug-arm"
       }
     ],
     "~followup_annotations": [
       "@@@STEP_TEXT@target-dartino-linux-debug-arm<br />target-dartino-linux-release-arm@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]