Make CrWinASan* bots true clobber bots.

scripts/slave/recipes/chromium.expected/full_chromium_fyi_CrWinAsan.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 111 matching lines @@
     "name": "swarming.py --version",
     "stdout": "/path/to/tmp/",
     "~followup_annotations": [
       "@@@STEP_TEXT@0.4.10@@@"
     ]
   },
   {
     "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",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]\\src",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json",
       "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "asan=1 clang=1 component=static_library enable_ipc_fuzzer=1 fastbuild=0 target_arch=ia32 test_isolation_mode=prepare v8_enable_verify_heap=1",
       "LLVM_FORCE_HEAD_REVISION": "YES",
       "PATH": "%(PATH)s;RECIPE_PACKAGE_REPO[depot_tools]"
@@ skipping 236 matching lines @@
     "~followup_annotations": [
       "@@@STEP_TEXT@CrWinAsan tester@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]