Add isolate.clean_isolated_files and use in all related recipes.

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.linux",
       "--builder",
       "Linux Builder",
@@ skipping 103 matching lines @@
       "python",
       "-u",
       "[BUILD]/scripts/slave/cleanup_temp.py"
     ],
     "name": "cleanup_temp"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "[BUILD]/scripts/slave/recipe_modules/isolate/resources/find_isolated_tests.py",
+      "--build-dir",
+      "[SLAVE_BUILD]/src/out/Release",
+      "--clean-isolated-files"
+    ],
+    "name": "clean isolated files"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[BUILD]/scripts/slave/compile.py",
       "--target",
       "Release",
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--build-tool",
       "ninja",
       "--compiler",
       "goma",
       "--goma-dir",
@@ skipping 71 matching lines @@
       "--build_revision",
       "170242",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.linux\", \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.linux\", \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "name": "package build"
   }
 ]