Use remove_build_metadata.py on all the trybots (take 3).

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "tryserver.chromium.linux",
       "--builder",
       "linux_arm",
@@ skipping 164 matching lines @@
       "base_unittests",
       "browser_tests",
       "mojo_common_unittests"
     ],
     "name": "compile (with patch)"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "[BUILD]/scripts/slave/recipe_modules/isolate/resources/remove_build_metadata.py",
+      "--build-dir",
+      "[SLAVE_BUILD]/src/out/Release",
+      "--src-dir",
+      "[SLAVE_BUILD]/src"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "remove_build_metadata"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "\nimport glob\nimport sys\nwith open(sys.argv[1], 'w') as f:\n  f.write('\\n'.join(glob.glob(sys.argv[2])))\n",
       "/path/to/tmp/",
       "[SLAVE_BUILD]/src/out/Release/*.isolated.gen.json"
     ],
     "name": "find isolated targets"
   },
   {
     "cmd": [
       "python",
       "-u",
@@ skipping 11 matching lines @@
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"dummy_target_1\": \"[dummy hash for dummy_target_1]\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"dummy_target_2\": \"[dummy hash for dummy_target_2]\"@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
       "@@@SET_BUILD_PROPERTY@swarm_hashes@{\"dummy_target_1\": \"[dummy hash for dummy_target_1]\", \"dummy_target_2\": \"[dummy hash for dummy_target_2]\"}@@@"
     ]
   }
 ]