Roll recipe dependencies (nontrivial).

scripts/slave/recipes/dart/dart_cross_compiler.expected/clobber-coverage.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.dart",
       "--builder",
       "test-coverage-stable",
       "--slave",
       "TestSlavename",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': 'DEPS', 'managed': False, 'name': 'sdk', 'url': 'https://chromium.googlesource.com/external/github.com/dart-lang/sdk.git'}]",
       "--root",
       "sdk",
       "--revision_mapping_file",
       "{}",
       "--git-cache-dir",
       "[GIT_CACHE]",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "sdk@abcd1234efef5656",
       "--force",
       "--output_manifest"
     ],
-    "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"did_run\": true, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"fixed_revisions\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"sdk\": \"abcd1234efef5656\"@@@",
@@ skipping 17 matching lines @@
     "cwd": "[SLAVE_BUILD]/sdk",
     "name": "clobber"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
       "runhooks"
     ],
-    "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/sdk/tools/build.py",
@@ skipping 30 matching lines @@
       "-a",
       "public-read",
       "cross_build_x64_release_abcd1234efef5656.tar.bz2",
       "gs://dart-cross-compiled-binaries/cross_build_x64_release_abcd1234efef5656.tar.bz2"
     ],
     "cwd": "[SLAVE_BUILD]/sdk",
     "name": "gsutil upoad tarball"
   },
   {
     "cmd": [],
-    "cwd": "[SLAVE_BUILD]",
     "name": "trigger",
     "trigger_specs": [
       {
         "builder_name": "target-arm-vm-linux-release-stable"
       }
     ],
     "~followup_annotations": [
       "@@@STEP_TEXT@target-arm-vm-linux-release-stable@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]