Add isolate.clean_isolated_files and use in all related recipes.

scripts/slave/recipes/swarming/canary.expected/linux_Debug.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.testing.master",
       "--builder",
       "TestBuilder",
@@ skipping 102 matching lines @@
     ],
     "env": {
       "GYP_DEFINES": "component=shared_library gomadir='[BUILD]/goma' target_arch=x64 test_isolation_mode=archive test_isolation_outdir=https://isolateserver-dev.appspot.com use_goma=1"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "[BUILD]/scripts/slave/recipe_modules/isolate/resources/find_isolated_tests.py",
+      "--build-dir",
+      "[SLAVE_BUILD]/src/out/Debug",
+      "--clean-isolated-files"
+    ],
+    "name": "clean isolated files"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[BUILD]/scripts/slave/compile.py",
       "--target",
       "Debug",
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--build-tool",
       "ninja",
       "--compiler",
       "goma",
       "--goma-dir",
@@ skipping 156 matching lines @@
       "--shards",
       "1",
       "--decorate",
       "--print-status-updates",
       "--verbose",
       "dummy_target_2/Linux/[dummy hash for dummy_target_2]/TestBuilder/571"
     ],
     "name": "dummy_target_2"
   }
 ]