Give autogen bots on client.drmemory a separate clobber step

scripts/slave/recipes/client.drmemory.recipe_autogen.expected/linux_cr_builder_clobber.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.drmemory",
       "--builder",
       "linux-cr-builder",
@@ skipping 66 matching lines @@
       "@@@SET_BUILD_PROPERTY@got_v8_revision@\"801ada225ddc271c132c3a35f03975671d43e399\"@@@",
       "@@@SET_BUILD_PROPERTY@got_revision_cp@\"refs/heads/master@{#170242}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision_cp@\"refs/heads/master@{#276089}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision_cp@\"refs/heads/master@{#43426}\"@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
+      "\nimport os, sys\nfrom common import chromium_utils # Error? See https://crbug.com/584783.\n\n\nif os.path.exists(sys.argv[1]):\n  chromium_utils.RemoveDirectory(sys.argv[1])\n",
+      "[SLAVE_BUILD]/src/out/Release"
+    ],
+    "name": "rmtree clobber",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import os, sys@@@",
+      "@@@STEP_LOG_LINE@python.inline@from common import chromium_utils # Error? See https://crbug.com/584783.@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@if os.path.exists(sys.argv[1]):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  chromium_utils.RemoveDirectory(sys.argv[1])@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[BUILD]/scripts/slave/runhooks_wrapper.py"
     ],
     "env": {
       "CHROMIUM_GYP_SYNTAX_CHECK": "1",
       "DEPOT_TOOLS_UPDATE": "0",
       "GYP_DEFINES": "build_for_tool=drmemory component=shared_library",
       "GYP_GENERATORS": "ninja",
       "LANDMINES_VERBOSE": "1"
     },
     "name": "gclient runhooks wrapper"
@@ skipping 22 matching lines @@
       "base_unittests",
       "browser_tests",
       "crypto_unittests",
       "ipc_tests",
       "media_unittests",
       "net_unittests",
       "printing_unittests",
       "remoting_unittests",
       "sql_unittests",
       "unit_tests",
-      "url_unittests",
-      "--clobber"
+      "url_unittests"
     ],
     "name": "compile"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]