Roll recipe dependencies (nontrivial).

scripts/slave/recipes/chromium_trybot.expected/full_tryserver_chromium_angle_win_angle_x64_rel_ng.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 40 matching lines @@
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
       "--revision",
       "src/third_party/angle@HEAD",
       "--output_manifest"
     ],
     "cwd": "[BUILDER_CACHE]\\win",
     "env": {
-      "PATH": "%(PATH)s;RECIPE_PACKAGE_REPO[depot_tools]"
+      "PATH": "RECIPE_PACKAGE_REPO[depot_tools];%(PATH)s"
     },
     "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@    \"src\": \"HEAD\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"src/third_party/angle\": \"HEAD\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
@@ skipping 268 matching lines @@
       "import sys; sys.exit(0)"
     ],
     "name": "mark: before_tests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]